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 The ice age in North America and its bea 
 
 3 1924 004 114 058 
 
The original of tiiis book is in 
 tine Cornell University Library. 
 
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THE ICE AGE 
 
 IN NOBTH AMERICA 
 
 AND ITS BEARIlSraS UPON THE 
 ANTIQUITY or MAN 
 
 BY 
 
 G. FREDERICK WRIGHT, D.D., LL.D., f.g.s.a. 
 
 Late aseietant on the Pennsylvania and United States Geological Surveys 
 Authorof " Logic of Christian Evidences," "Greenland Ice Fields," " Asiatic Russia," etc. 
 
 Fifth e(|ItIon with, many new maps and Illustrations, enlarged 
 and rewritten to Incorporate the facta that bring 1 1 up to date, 
 with chapters on Lake Agaaslz and the Probable Cause of 
 Glaclatlon, by Warren Upham, Sc.D., F.G.S.A., late Assistant 
 on the Geological Surveys of New Hampshire, Minnesota, the 
 United States, and Canada. 
 
 OBERLIN, OHIO 
 BIBLIOTHECA SACRA COMPANY 
 
 1911 
 
COPTHIQHTBD 1911 
 
 BIBLIOTHECA SACRA CO. 
 
TO 
 ELISHA GEAY 
 
 CHETALIEB D£ LA LESION d'hONNEUR 
 
 mVENTOR OF THE HARMONIC TELEGRAPH, THE TELEPHONE 
 
 AND THE TELAUTOGRAPH 
 
 WHOSE INTELLIGENT INTEREST IN GLACIAL GEOLOGY 
 
 AND WHOSE GENEROUS APPRECIATION OF MY WORK 
 
 HATE BEEN A CONSTANT INSPIRATION 
 
 THIS VOLUME IS AFFECTIONATELY DEDICATED 
 
PREFACE TO THE FIFTH EDITION. 
 
 The twaaty years wMcfii haVe elapsed since the pufelica- 
 tidn of the first edition have fceeri exceedingly fruitful in 
 glacial investigations, as will be seen fey consulting the bibliog- 
 raphy at the end of this voluftie. Nevertheless, as premised 
 in the preface to the first edition, these later investigations 
 have not seriously affected the main theories adopted twenty 
 years ago; but "p6rtain mainly to the detail's of the subject." 
 
 In the present revision the fiew material added is especially 
 abundant only upon a few subjects. Many existing glaciers 
 have been dfecovered in the Rocky Mountain system in the 
 tJnited States and Canada — a region which was scarcely 
 touched' by explorers until the close of the last century. 
 Explorations have also greatly extended our knowledge of 
 Alaskan glaciers while the changes in the Muir Glacier have 
 been so enormous as t6' be really startling, fully sustaining 
 the theoretical conclusions ■v^hich I had drawn from my stud- 
 ies of the glacier in 1886. Much new material, also, has 
 aecumtilated concerning the glaciers of Greenland, Central 
 Asia, and the Antarctic Continent. 
 
 As to the extent of the continental glaciers of the Pleisto- 
 cene period, there has been little additional information 
 since the publication of the first edition. Among the most 
 important additions has been the rectification of the glacial 
 boundary across New Jersey and Pennsylvania, where the 
 "fringe," or "attenuated border," imperfectly apprehended 
 by Lewis and Wright, has been carefully traced by Professor 
 
VI PREFACE TO FIFTH EDITION. 
 
 E. H. Williams from the Atlantic Ocean to Ohio and found to 
 be from twenty to thirty miles south of their terminal moraine. 
 
 The facts relating to this border, brought out by Professor 
 WiUiams, have a most important bearing upon the discus- 
 sion both of the cause and of the date of the Pleistocene glacial 
 epoch. 
 
 There has also been a great accumulation of evidence, 
 collected pretty largely by Mr. Frank Leverett ajid the geolo- 
 gists of Iowa, Minnesota, Dakota, and Canada, concerning 
 the episodes of the Pleistocene glacial epoch, leading to the 
 division into the Kansan, Illinoisan, lowan, and Wisconsin 
 periods of advance and retreait. The relative length of time 
 occupied by these episodes is still a most interesting subject of 
 investigation. 
 
 The question of the date of the Pleistocene glacial epoch is 
 still a subject of hot discussion, but a great accumulation of 
 facts, relating to post-glacial erosion and sedimentation, are 
 rapidly establishing a very moderate glacial chronology. 
 
 Likewise a great accumulation of facts is limiting the the- 
 ories concerning the cause of glaciation to changes in land 
 elevation and in the direction of oceanic currents. The chap- 
 ters upon the date and the cause of the epoch have been 
 greatly enlarged and rewritten. 
 
 The final chapters upon the discovery of human relics in 
 deposits connected with the Glacial epoch in North America 
 have also been thoroughly revised and enlarged, to take into 
 consideration the more recent discoveries of facts bearing 
 both for and against man's existence here in glacial times. 
 
 G. Frederick Wright. 
 Obbrlin, Ohio, December 22, 1910. 
 
PREFACE TO FIEST EDITIOIsr. 
 
 The present treatise is the outcome of special studies 
 upon glacial phenomena begun in the summer of 1874, in 
 the eastern part of Massachusetts, the results of which 
 were published in a communication to the Boston Society 
 of Natural History in December, 1876. These first studies 
 pertained to the origin of the gravel-ridges described in 
 this volume under the name of "kames." Fortunately, 
 in the preparation of that paper, I was favored with an 
 interview with Mr. Clarence King, who then gave me the 
 information referred to in the following pages, concerning 
 the terminal moraine south of N^ew England, which has 
 been so fruitful of suggestion to other investigators as 
 well as to myself. Since that time the subject has never 
 been out of mind, and my summer months have all been 
 devoted, under favorable conditions, to the collection of 
 field notes regarding it, and so it has seemed to others, as 
 well as to myself, appropriate that I should endeavor to 
 bring the facts within the reach of the general public. 
 
 After having become, during the four following sea- 
 sons, familiar with the glacial phenomena over the larger 
 part of New England, I was invited by Professor Lesley 
 to survey, in company with the late Professor H. Carvill 
 Lewis, the boundary of the glaciated area across Pennsyl- 
 
viii PREFACE TO FIRST EDITION. 
 
 vania (our report constitutes Vol. Z of the Second Geologi- 
 cal Survey of that State). The summers of 1882 and 1883 
 were spent under the auspices of the Western Reserve His- 
 torical Society of Cleveland, Ohio (whose secretary, Judge 
 C. C. Baldwin, had the sagacity to recognize, at that early 
 time in the investigations, the historical bearing of the 
 work), in continuing the survey across Ohio, Kentucky, and 
 Indiana (see my report to that society, 1884, and an article 
 in the "American Journal of Science," July, 1883). Dur- 
 ing the summers of 1884 and 1885 I was employed, as a 
 member of the United States Geological Survey, in tracing 
 the boundary across Illinois, and in reviewing the field in 
 Ohio and western Pennsylvania. The report of this work 
 has not yet been made public, but permission to use the 
 facts has been generously granted by the director of the 
 sufvey, lifajor J. W. Powell. The summer of 1886 was 
 spent in Washijigton Territory, and upon the Muir Glacier 
 in Alaska. The two following seasons were occupied in 
 further exploration of Ohio, Dakota,, and other portions of 
 the Northwest. Thus I have personally been over a large 
 part of the field containing the wonderful array of facts of 
 which I anj now permitted to write. 
 
 In the autumn of 1887 I was invited to give a course 
 of lectures upon the Ice Age in North America before the 
 Lowell Institute in Boston, and in the following year be- 
 fore the Peabody Institute in Baltimore. Fo;r the inforfna- 
 tion of the audiences who heard those courses of lectures it 
 is proper to say that the present treatise incorporates all 
 the facts then presented, though in a difierent form. The 
 volume covers, however, a much wider field than the lect- 
 ures, and is mo.re ample in its treatment of all the topics. 
 
 But it is not to be supposed that a single person can 
 
PREFACE TO FIRST EDITION. ix 
 
 adequately survey so large a field. The writer is but one 
 of many investigators who have been busily engaged for 
 the past fifteen years (to say nothing of what had been 
 previously accomplished) in collecting facts concerning the 
 Glacial period in this country. My endeavor has been to 
 make the present volume a pretty complete digest of all 
 these investigations, and in carrying out that aim I have 
 had the generous assistance of the great array of careful 
 and eminent observers who have turned their attention to 
 the subject. So far as possible I have, by their permission, 
 given their results in their own language, and with due 
 credit. I hereby take occasion to express my obligations 
 for the help which they have, one and all, so courteously 
 rendered. 
 
 The numerous maps accompanying the text have been 
 compiled from the latest data, as indicated in the abundant 
 foot-notes scattered throughout the volume. These render 
 it unnecessary to make here any more specific acknowl- 
 edgment of authorities. 
 
 The volume is committed to the public in the belief 
 that it will meet a widely felt want. The accumulation 
 of facts for the past decade has been so rapid, and from so 
 many sources, that few persons have been able to keep 
 themselves informed of the progress made. And so great 
 has this progress been that we may now safely assume that 
 future discussions will pertain mainly to the details of the 
 subject. "We now know, from actual observation, the limits 
 and prominent characteristics of the glaciated area on this 
 continent. The Glacial age of North America is no longer 
 a theory, but a well-defined and established fact. 
 
 It will become apparent also that, though the title of 
 the book is the " Ice Age in North America," it is really 
 
X PREFACE TO FIBST EDITION. 
 
 a treatise on the whole subject of the Glacial period ; for, 
 with the vast field open for investigation on this continent 
 and the amount of attention recently given to its explo- 
 ration, North America is now by far the most favorable 
 place from which to approaeb the study of ice-action and 
 ice periods. 
 
 The last chapters of the volume treat of man's relation 
 to the lee age on this continent ; and I need not di^uise 
 the fact that the bearing of the discoveries upon this ques- 
 tion has all along given zest to my investigations. The 
 facts with regard to this subject also are now so far in 
 hand that they can he properly discussed in ai treatise de- 
 signed in part for the general public. 
 
 While presenting as fully as is necessary the evidence of 
 man's occupancy of the continent during the great Ice age, 
 and while accepting this as aecessitating a considerable 
 extension of man's antiquity as usually estimated, I have 
 not felt called upon in the present discussion to say any- 
 thing about the method of reconciling this fact with the 
 chronology of the human race supposed to be given in the 
 sacred Scriptures ; for I have elsewhere (in my " Studies 
 in Science and Eeligion," W. F. Draper, Andover, 1882, 
 and " Divine Authority of the Bible," Congregational Pub- 
 lication Society, Boston, 1884) said all that it seems at 
 present necessary for me to say upon this poiat. I will 
 only remark here that I see no reason why these ^iews 
 should seriously disturb the religious faith of any believer 
 in the inspiration of the Bible. At all events, it is incum- 
 bent on us to welcome the truth, from whatever source it 
 may come. 
 
 Gr. Feedeeick Weight. 
 
 Oberlin, Ohio, April 15, 1889. 
 
CONTENTS 
 
 CHAPTER I. 
 
 „, •■AGE 
 
 What is a Glacier? ]__12 
 
 The Appearance of Ice deceptive, 1 ; Discovery of Its Real Nature, 2 ; Motion of a 
 Glaeler,2 ;Effectof rrlctlon,3 ; Cause of the Motion, 4 ; Plasticity of Ice, 5 [Rela- 
 tion of Snow to lee, 6 ; Structure of a Glacier, 7 ; Veins, 7 ; Fissures, 8 ;Ice-PlIlars, 
 10 ; Terminal Moraines, 10 ; Kames, 11 ; Glacial Scratches and Groovlngs, 12. 
 
 CHAPTER II. 
 Existing Glaciers on the Pacific Coast . . . 13-39 
 
 In Southern California, 13 ; In Northern California: Mount Shasta, 15 ; In Oregon, 
 19 ; In Washington Territory: Mount Tacoma, 19 ; British Columblaand Alaska, 
 23 ; on the Stlckeen Blver, 25 ; in Taku Inlet: Norrls Glacier, 27 ; In Lynn Canal: 
 Davidson Glacier, 27 ; north of Cross Sound, 29 ; on Mt. St. Ellas, 30 ; In 
 Yakutat Bay, 30 ;north of theAlaskan Peninsula, 36. 
 
 CHAPTER III. 
 A Month with the Mtjie Glacier . 40r74 
 
 Purposes of the Expedition, 40 ; Facilities for Observation, 41 ; Description of 
 Glacier Bay and Its Surroundings, 41 ; Mulr Inlet, 43 ; Dimensions of the Mulr 
 Glacier, 43 ; Various Characteristics, 47 ; Moraines, 49 ; Indirect Evidences of 
 Motion, 50; Formation of Icebergs, 51 ; Subglaclal Streams, 51 ; Direct Measure- 
 ment of Velocity, 52 ; Retreat of the Ice-front, 55 ; Former Extension of the Glacier, 
 59 ; a Burled Forest, 61 ; Kamesand Kettle-holes, 66 ; Transportation and Waste , 
 by Water, 67 ; Temperature In August, 68 ; Floraof the Vicinity, 69 ; H. F. Reld's 
 Measurements, 71 ; F. E. and C. W. Wright's Observations, 72. 
 
 CHAPTER IV. 
 Glaciers of Greenland . . 75-102 
 
 Extent of Greenland, 75 ; Nordensklold's Expedition, 75 ; Amount of Coast Line 
 already explored, 77 ; Number of First-class Glaciers In Danish Greenland, 78 ; 
 Movementof Ice Inthem, 78 ;Nunataks, 71 ; Former Extension ofthelce, 79 ; 
 Holland's Observations, 80 ; Whymper'a Description, 83 ; Explorations of Kane 
 and Hayes, 86 ; Humboldt Glacier, 92 ; Glaciers on the Eastern Coast of Green- 
 land, 97 ; Nansen's Expedition, 98 ; Erlchsen's Expedition, 99 ; Hoist's Obser- 
 vations on Frederlckshaab Glacier, 100. 
 
 xi 
 
Xii CONTENTS. 
 
 CHAPTER V. PAGE 
 
 GiiAciBHs IN Other Parts of the World . . . 104^121 
 
 In the Alps, 104 ; In Scandinavia, 106 ; In Spltzbergen, Franz-Josef Land, and Ice- 
 land, 107 ; In Asia, 107 ; In South America, 108 ; Darwin's Account, 109 ; In New 
 Zealand, 112 ; on the Antarctic Continent, 112 ; Icebergs of the Southern Ocean, 
 115 ; CroU's Inferences from the Size of these Bergs, 118 ; Shaokleton's Expedition 
 to the Antarctic, 120. • 
 
 CHAPTER VI. 
 Signs of Glaciation 122-133 
 
 Introductory Remarks, 122 ; Groovesand Scratches, 123 ; Sir Charles Lyell's Ob- 
 servations In Nova Scotia, 126 ; the Ground Moraine, or "Till," 129 ; Cause of Its 
 being unstratlfied, 130 ; Sifting Power of Water, 131 ; Distribution of Bowl- 
 ders, 132. 
 
 CHAPTER VII. 
 Boundary of the Glaciated Area in North America 134-193 
 
 Confluent Character of the Ice-sheet, 134 ; Progress of Discovery, 134 ; Elements 
 determining the Amount of Glacial Deposition, 135 ; Counteracting Influence of 
 Subglaclal Streams, 136 ; Influences determining the Amount of Marginal De- 
 posits, 137 ; south of New England, 137 ; Interior Marginal Deposits, 139 ; 
 Long Island a Moraine, 140 ; Marginal Deposits across New Jersey, 140 ; Rela- 
 tlonofKettle-holestothe Moraines, 143 ; Marginal Deposits In Eastern Pennsyl- 
 vania, 144 : Western NewYork and Pennsylvania, 149. 
 
 CHAPTER VII (continued). 
 
 The Attenuated Border 151-166 
 
 Lineof,lS3 ; Lake Williams, 153 {Character of Material In, 154 ; Lake Lesley, 156 ; 
 Lake Allegheny, 153 ; Changes of Land-level, 160 ; Valleys of the Allegheny 
 River, Conewango Creek, and Ohio River, 161. 
 
 CHAPTER VII (concluded). 
 The Glacial Boundary West of Pennsylvania . 167-193 
 
 Marginal Deposits through Ohio, 167 ; Extension of the Ice Into Kentucky, 170 ; 
 Course of the Boundary In Indiana and Illinois, 170 ; Boundary west of the Miss- 
 issippi, 172 ; west of the Rocky Mountains, 176 ; Ancient Glaciers In Southern 
 California, 179; Glacial Boundary north of Puget Sound, 183 ; near the Head- 
 waters of the Yukon, 190; Summary of Facts regarding the Padflo Coast, 190. 
 
 CHAPTER VIII. 
 Depth of Ice during the Glacial Period . . 194-202 
 
 Means of Estimating it, 194 ; Mountain Summits covered in New England, New 
 York, and Pennsylvania, 194 ; Depth estimated from the Distance moved, 199 ; 
 Slope of a Glacier, 201. 
 
CONTENTS. xiii 
 
 CHAPTER IX. PAOE 
 
 Terminal Moraines 203-225 
 
 Indefinlteness of the Term, 203 ; Prominence of the Moraine south of New Eng- 
 land, 20i ; Detalla respecting the Kettle-holes In this Fart of the Moraine, 205 ; 
 Submerged Portions of the Moraine, 206 -, Moraines of the Middle States, 207 ; 
 President Chamberlln on the Moraines west of the Alleghanles, 207 ; Gilbert on 
 the Moraines of the Maumee Valley, 207 ; the Kettle Moraine of Wisconsin, 211 ; 
 Battleofthe GlaclerslnMlnnesotaand Wisconsin, 212 ; Moraines In Dakota,2 14 ; 
 In Central British America, 217 ; Later Moraines In the White Mountains, 221 ; 
 on the Sierra Nevada and Cascade Mountains, 222 ; Moraines of the Wisconsin 
 Episode, 222 ; Bllnolsan Deposits, 223 ; lowan Deposits, 223 ; Kansas Deposits, 
 221 ; the Aftonlan Episode, 224. 
 
 CHAPTER X. 
 
 GLAciAii Erosion and Transportation . . . 226-280 
 
 Erosive Action of Ice compared with that of Running Water, 226 ; Chemical 
 Action of Water, 229 ; Danger of exaggerating the Erosive Action of Ice, 230 ; 
 Glacial Erosion least near the Margin, 233 ; Analogy between the Glacial Front 
 and Breakers In the Ocean, 234 ; Transportation of Bowlders on the Surface of a 
 Glacier, 236 ; Details respecting. In Southern New England, 237 ; In Richmond, 
 Mass., 239 ; In New Jersey and Pennsylvania, 241 ;lnOhIo, 242; In Southern In- 
 diana and nilnols, 243 ; In Iowa and Dakota, 243 ; In British America, 244 ; Ele- 
 vation of Bowlders In the Ice, 246 ; Explanation of, 248 ; Erosion of Subgladal 
 Streams, 254 ; Erosion estimated by the Amount of Till, 257 ; Attempts at Direct 
 Measurement of Glacial Erosion near the Delaware Water-Gap, 260 ; affected by 
 Preglaclal Disintegration, 261 ; Evidence of , near Western End of Lake Erie, 262; 
 In the Sierra Nevada. 267 ; Summary, 279. 
 
 CHAPTER XI. 
 
 Drumlins 281-297 
 
 Definition, 281 ; those In the Vicinity of Boston Enumerated, 281; Mr. Upham's 
 Description, 282 ; Series of, In Rockingham County, N. H., and Essex County, 
 Mass., 284 ; Occurrence of. In the Interior of the Country, 285 ; Theory of their 
 Formation, 287; Irregularities of Glacial Erosion and Deposition, 294. 
 
 CHAPTER XII. 
 Freolacial Drainage . 298-312 
 
 Length of Preglaclal Time, 298 ; extent of Preglaclal Erosion, 299 ; the Trough of 
 the Ohio preglaclal, 300 ; Other Preglaclal Valleys, 302 ; Preglaclal Drainage of the 
 Great Lakes, 304 ; Preglaclal Drainage of the Upper Allegheny River Into Lake 
 Erie, 307. 
 
 CHAPTER XIII. 
 
 Drainage op the Glacial Period .... 313-337 
 
 Obstruction of Ice-barriers across the Red River of the North, the St. Lawrence, 
 and the Mohawk, 313 ; Closing Floods of the Glacial Period, 314 ; Terraces pro- 
 duced by these Floods In the Trough of the Mississippi; In the Minnesota, 315 ; 
 
xiv CONTENTS. 
 
 FAOa 
 
 In the Northern Tributaries of the Ohio, 323 ; In the Streams of Northern Pennsyl- 
 vania, 325 ; Material composing the Glacial Terraces, 325 ; such Terraces absent 
 from Streams wholly In the Unglaclated Region, 325 ; Terraces on the Ohio, 327 ; 
 on Beaver Creek, Pa., 328 ; on the Delaware, 289 ; Relation of Pot-holes In Graf- 
 ton, N. H., to Glacial Drainage, 330 ; Similar Phenomena In Lackawanna County, 
 Pa., 331 ; Remarkable Evidence of Abnormal Glacial Drainage In Dakota, 332 ; 
 Marginal Drainage In the Northwest, 334. 
 
 CHAPTER XIV. 
 
 Kames 339-354 
 
 In Andover, Mass., 339 ; Definitions, 339 ; Gelkle's Description , 339 ; Relations of 
 Kames to Terminal Moraines, 340 ; Origin of, 341 ; Indicate Lines of Temporary 
 Glacial Drainage, 342 ; Lines of, In New England enumerated, 343 ; Questions 
 reepectlng.lnthe Connecticut River Valley,345 ;PossIbleExtentof GlaoIalFloods 
 In thu Valley, 346 ; Relation of Sandy Plains to Kames, 348 ; Existence of Kames 
 foretold, 349 ; Overwash Gravel limited In Amount, 350 ; Abnormal Relation of 
 Kames to the Slope, 351 { Summary, 353. 
 
 CHAPTER XV. 
 
 Glacial Dams, Lakes, and Waterfalls 355-406 
 
 Rock Basins eroded by Glaciers, 355 ; Theory of the Great Lakes, 356 ; Two 
 Classes of Glacial Dams, 350 ; Kettle-hioles, 359 ; Relation of, to Peat-bogs and to 
 Terminal Moraines, 360 ; Lakes formed by Permanent Obstruction of Preglaclal 
 Channels, 362 ; the Formation of Waterfalls, 362 ; Temporary Lakes formed by 
 Ice Barriers, 363 ; Supposed Glacial Dam In the Ohio, at Cincinnati, 366 ; Evi- 
 dence that the Ice crossed the Ohio, 367 ; Consequences of such an Obstruction, 
 368 ; History of Its Discovery, 370 ; Theory discussed by the American Associa- 
 tion for the Advancement of Science, 371 ; Theory confirmed by the Absence of 
 Terraces In Brush Creek, Ohio, 372 ; by the Terrace at Bellevue, Pa., 375 ; Diffi- 
 culty of Other Explanations, 376 ; the Occurrence of Vegetable Matter in the 
 Terraces of theMonongahela support the Theory, 377 ; Teazes Valley, W. Va., ex- 
 plained by the Theory, 379 ; Various Other Phenomena explained In a Similar 
 Manner, 382 ; Objections considered, 383 ; Claypole on, 386 ; Glacial Dam In the 
 Monongahela, 39} ; the Lake Ridges of Ohio and New York, 395 ; Glacial Dam 
 acrossthe Mohawk and the St. Lawrence, 398 ; Glacial Lake In the Red River 
 Region of the North : Lake Agasslz , 401 . 
 
 CHAPTER XVI. 
 
 The Loess . . . . 407-421 
 
 Extent of the Deposit In China and North America, 407 ; Rlclithofen's Theory 
 of Deposition by Wind, 408 ; Difficulties of the Theory, 410 ; Characteristics of, 
 412 ; Changes of Level Necessary, 413 ; Probable Connection with Glacial Floods, 
 415 ; Supplementary Theories, 417. 
 
 CHAPTER XVII. 
 
 Plight of Plants and Animals dtjbing the Glacial 
 
 Period 422-444 
 
 Peculiar Distribution of Plants In the North Temperate Zone, 422 ; Professor 
 Asa Gray's Solution of the Problem, 424 ; more Detailed Statement by Professor 
 Gray, 425 ; Comparison of the Pacific with the Atlantic Forests, 426 ; Oomparlson 
 
CONTENTS. XV 
 
 PAOB 
 
 of both with those of Japan, North China, and Europe, 427 ; Number of Pre- 
 glaclal Species now found In the Temperate Zone, 430 ; our Treea originated In the 
 High Latitudes, 432 ; the Vicissitudes to which they have been subjected since 
 the Approach of the Glacial Period, 433 ; Open Lines of Emigration In America, 
 434 ; Peculiar Influences upon the Pacific Coast, 435 ; Extinction of Animals In 
 America by the Glacial Period, 436 ; Alpine Butterflies upon the White Moun- 
 tains, 438 ; List of Plants common to the Okhotsk-Kamchatkan Region and 
 North America, 441. 
 
 CHAPTER XVIII. 
 Europe during the Glacial Period . . . 445-459 
 
 Glaciated Area In Great Britain, 445; on the Continent, 447; Investigations 
 of Professor Lewis, 448; Summary of Conditions In Great Britain by Dr. 
 Harmer, 454; Investigations of Professor Salisbury, 4S6. 
 
 CHAPTER XIX. 
 
 The Cause or the Glacial Period . 461-494 
 
 Recent Astronomical Speculations, 461 ; the Combination of Conditions necessary 
 to produce a Glacier, 461 ; Theories to account for the Glacial Period, 463 ; Decrease 
 of the Original Heat of the Planet, 463 ; Shifting of the Earth's Axis of Rotation, 
 463; Theory of Progressive Deslcatlon, 464; Depletion of Carbon Dioxide In the 
 Atmosphere, 464; Different Temperatures of Space, 465; Mr. Croll'a Theory: the 
 ElUptlcIty of the Earth's Orbit and the Precession of the Equinoxes, 466; Possible 
 Effect of these upon the Climate, 467; Cause of the Gulf Stream, 469; Causes con- 
 trolling the Distribution of the Heat from the Sun, 477; WoelkoS's Objections to 
 Croll's Theory, 479; Supposed Evidence of Former Glacial Periods, 483; Carbon- 
 iferous and Cambrian Glacial Periods now established, 490. 
 
 CHAPTER XIX (continued). 
 The Cause of the Glacial Period .... 495-531 
 
 Effect of Changes In the Distribution of Land and Water, 495 ; Theory of Changes 
 of Level, 496; Supplementary Notes by Warren Upham, 520; produced by the 
 Accumulation of Snow over Definite Centers, 525; Field for Mathematical Inves- 
 tigation, .528; Summary, 529. 
 
 CHAPTER XX. 
 
 The Date of the Glacial Period .... 532-615 
 Uncertainty of Astronomical Calculations, 532; Detect in Lyell's Theory of Unl- 
 f ormltarlanism , 533 ; Post-glacial Erosion below Niagara Falls, 536 ; below Falls of 
 St. Anthony" 552; in Ohio, 560; Freshness of the Glaciated Surfaces, 568; Post-gla- 
 cial Erosion In Minnesota, 571 ; about Lake Michigan, 571 ; Post-glacial Deposition 
 In Kettle-holes, 572 ; the Question of Two or More Post-tertiary Glacial Epochs, 575 ; 
 Greater Oxidization of Material near the Glacial Boundary, 579; Freshness of In- 
 terglaclal Forest^beds, 592; Growth of Peat, 594; Extent of Forest-beds, 603; 
 Former Extension of Lakes Bonneville and Lahontan, 607; Recentness of these 
 Lakes, 610; Length of the Glacial Period, 613; Summary, 614. 
 
XVI CONTENTS. 
 
 CHAPTER XXI. PAQB 
 
 Man and the Glacial Period .... 616-668 
 
 Prominence given by Lyell to the Subject, 616; Artificiality of the Implements, 
 617; Professor Hayneson, 619; Genuineness of, 622; Discoveries of Boucher de 
 Perthes In France, 621; of other Investigators In England, 634; of Dr. Abbott In 
 New Jersey, 625; Nature of the Gravel at Trenton, 630; Mode of Deposition, 634; 
 Series of Events In the Delaware Valley, 639; Discoveries in Ohio foretold, 640; 
 Discoveries by Dr. Metz, In Ohio, 642 ; Deposit at Madlsonvllle, Ohio, described, 
 644; Discovery by Mr. Mills at Newcomerstown, Ohio, 645; Discovery by Mr. 
 Huston at Brilliant, Ohio, 648; Cresson's Discoveries at Medora, Ind., 649; Wln- 
 chell's Discoveries In Morrison County, Minn., 653; Miss Babbitt's Discoveries 
 at Little Falls, Minn., 654; Upham's Discussion of the Deposits In Minne- 
 sota, 654. 
 
 CHAPTER XXII. 
 Man and the Glacial Period (Continued) . . 669-676 
 
 Cresson's Discoveries at Claymont, Del., 669; Prehistoric Development In the 
 Delaware Valley, 674. 
 
 CHAPTER XXIII. 
 
 Man in the Missouri Valley . . 678-686 
 
 Discovery at Lansing, Kan., 678; Natureof the Deposit at Lansing, Kan., 679; 
 Nebraska Loess-Man, 683; Nature of Deposit in which found, 683; Discovery at 
 St. Joseph, Mo., 685. 
 
 CHAPTER XXIV. 
 
 Man and the Lava Beds op the Pacific Coast . 687-709 
 
 Whitney's Discoveries in California, 688; Le Conte on the Quaternary Deposits 
 of California, 689; Whitney's Evidence In Detail, 692; Stone Mortars from under 
 Table Mountain, 694; Criticism of Whitney, 697; the Nampa Image, 701; Conclu- 
 sion, 706. 
 
 BIBLIOGRAPHY 711-741 
 
 INDEX 743-763 
 
LIST OF ILLUSTRATIONS 
 
 Front of Mulr Glacier, Alaska, from the southeast comer, looking across the sur- 
 face and up one of the tributaries . . . . Frontispiece. 
 
 FXO. PAGE 
 
 1. Differential motion of Ice . . 2 
 
 2, 3. Differential motion of ice S 
 
 4. Plasticity of Ice 6 
 
 5. Fissures and seracs 8 
 
 6. 7. Marginal fissures and veins . 8 
 
 8. Veined structure at the junction of two branches 9 
 
 9. Mode of formation of Ice-plllars , 10 
 
 10. Moraines of the Mer de Glace . . . 10 
 
 11. Glacial scorings . . 12 
 
 12. West end of Samovar Glacier, Alaska . . 14 
 
 13. Mount Shasta, California. (Russell.) ... . . .17 
 
 14. Mount Tacoma, Washington State, looking westward. (Charles S. Fee.-) 20 
 
 15. Mount Tacoma, Washington State, looking eastward. (Charles S. Fee.) 21 
 
 16. Map of southeastern Alaska . ... 24 
 
 17. Norris Glacier, Alaska. (Partridge.) . . 26 
 
 18. Glacier Station, British Columbia. (Canadian Pacific Railroad.) 28 
 
 19. Davidson Glacier, Alaska ... . . 29 
 
 20. Map showing hypothetical former extension of glaciers. [U. S. Geological 
 
 Survey.) . . 31 
 
 21. Map of Alaska .... 34 
 
 22. Sketch map of Glacier Bay and Mulr Glacier, (H. F. Reid.) 44 
 
 23. Looking across front of Mulr Glacier, Alaska . 46 
 
 24. Map of Mulr Inlet, Alaska . . . 53 
 
 25. Surface of Mulr Glacier. (Partridge.) 56 
 
 26. Formation of kettle-hole. Alaska. (Partridge.) . 58 
 
 27. Burled forest on the Mulr Glacier ... 62 
 
 28. Buried forest. Glacier Bay, Alaska 65 
 
 29. Mulr Glacier from an elevation of 1,800 feet 65 
 
 30. Ice-pillars. (Russell.) . 70i 
 
 31. Map of Greenland . . 76. 
 
 32. Map of Frederlckshaab Glacier, Greenland. (Dana.) . . 81i 
 
 33. Ikamiut Fjord, Greenland, showing hanging glaciers . 83: 
 
 34. Sea margin of Cornell Glacier, Greenland . ... 103 
 
 35. Glacier in North Greenland, showing upper strata of ice rolling over like breakers 105 
 
 36. Morteratsch Glacier, Switzerland 105 
 
 37. Svartisen Glacier, Norway. (Waroer.) ... . . 106 
 
 38. Iceberg . ... . . 116 
 
 39. Floating berg . . . .119 
 
 40. Scratched stone from till of Boston. Mass. . . . . 12S 
 
 xvii 
 
XVlll 
 
 LIST OF ILLUSTRATIONS. 
 
 41. 
 42. 
 43. 
 44. 
 45. 
 46. 
 47. 
 48. 
 49. 
 50. 
 51. 
 52. 
 S3. 
 54. 
 55. 
 56. 
 57. 
 58. 
 59. 
 60. 
 61. 
 '62. 
 63. 
 64. 
 65. 
 66. 
 67. 
 68. 
 69. 
 70. 
 71. 
 72. 
 73. 
 '74. 
 76. 
 '76. 
 77. 
 78. 
 79. 
 80. 
 81. 
 82. 
 83. 
 84. 
 85. 
 86. 
 87. 
 
 Glacial 3trl8D, Amherst, Ohio. (Chamberlln.) 
 Cut in till, Hamilton, Ohio . 
 Cut In till, Darrtown, Ohio .... 
 Glacial map of southern New England 
 
 121 
 12j 
 131 
 138 
 
 Glacial map of New Jersey 141 
 
 Glacial map of Pennsylvania and southern New York 
 
 Glaciated pebble, Pennsylvania . . . ... 
 
 The same, side view .... 
 
 Attenuated border, eastern Pennsylvania, (Williams.). . 
 
 Lake Lesley, Pennsylvania 
 
 Advance of Wisconsin Ice over the Kansan border near the apex of New York 
 Lake Allegheny ... ... . . 
 
 Map of the upper Allegheny Valley, Pa. . . . 
 
 Sand pit at Warren, Pa. . . . ■ 
 
 Bar at Warren, Pa. 
 
 Glacial map of Ohio 
 
 Glacial map of southern Indiana 
 
 Glacial map of southern Illinois . . . . 
 
 Typical section of till in Seattle, Washington State 
 Section of modified drift at Point Wilson, Washington State 
 Glacial groovlngs, Victoria, British Columbia 
 Glacial map of North America ... 
 
 Depth of ice and erosion In eastern Pennsylvania. (Lesley.) 
 
 Map of kettle-holes near Wood's Holl, Mass. 
 
 Map of moralnal deposits, western New York. (IT. S. Geological Survey. 
 View of kettle-moraine. Eagle, Wis. (Chamberlln.) 
 
 Map of the MlBuourl coteau. (Todd.) 
 
 Glacial map of central British America. (Dawson.) 
 
 The Missouri coteau. (Dawson.) . . . . 
 
 Canon of the Colorado. (Newberry.) 
 
 Embossed floor of an ancient glacier, Colorado. (Hayden.) 
 
 Glacial bowlder, Gllsum, N. H. (Hitchcock.) 
 
 Mobegan Kock, Montville, Conn. . 
 
 Glaciated pebble, Indiana 
 
 Reverse side of the same 
 
 Ideal section showing distribution of till .... 
 
 Ideal section showing sub-a€rlal disintegration. (Chamberlln.) 
 
 Glacial grooves. South Bass Island, Lake Erie 
 
 TortUcua glacial grooves, Kelley's Island, Lake Erie. (Chamberlln.) 
 
 Section of glacial furrows, Kelley's Island, Lake Erie 
 
 Full view of the same. (Younglove.) . . . . 
 
 Glacial furrows, South Bass Island, Lake Erie , 
 
 Glacial furrows, Gibraltar Island, Lake Erie 
 
 Cross striae. Middle Bass Island, Lake Erie 
 
 lowan bowlders. (Calvin.) ... 
 
 Map of drumllns near Boston. (Davis.) . ... 
 
 View of Corey's Hill, Brookllne, Mass. A typical drumlln. (Davis.) 
 
 Outline of druralins In Boston Harbor. (Davis.) 
 
 Map of drumllns in northeastern Massachusetts. (Davis.) 
 
 Outline of drumllns, central New York. (Davis.) .... 
 
 Drumllns in Wisconsin. (Chamberlln.) . . . . 
 
 Drumllns in Goffetown, N. H. (Hltohcock.) 
 
 Drumllns in Ireland. (Klnnehan and Close.) 
 
 Section of the valley of the Cuyahoga River. (Claypole.) 
 Cross-section showing old and new channels of the Mlsalaslppi River. (Iowa 
 GeologlcalSurvey.) 
 
 145 
 146 
 147 
 152 
 157 
 157 
 159 
 165 
 167 
 167 
 168 
 171 
 173 
 181 
 182 
 184 
 191 
 196 
 205 
 206 
 210 
 216 
 218 
 219 
 226 
 227 
 236 
 238 
 252 
 253 
 257 
 261 
 263 
 264 
 267 
 268 
 270 
 272 
 275 
 280 
 281 
 232 
 283 
 284 
 285 
 286 
 237 
 291 
 304 
 
 310 
 
LIST OF ILLUSTRATIONS. xix 
 
 96. Drainage map of southeastern Iowa. (Leverett.) . . 318 
 
 97. Cross-section of the Osage trough at Tuscumbla, Mo. . 318 
 
 98. Map showing glaciated and unglaclated portions of Missouri . 322 
 
 99. Glacial terrace, Granville, Ohio . .323 
 
 100. Map of South Dakota showing the channel of the Missouri River . 335 
 
 101. Maps of kames in eastern Masschusetts . 338 
 
 102. Section of kame, Dover, N. H. (Upham.) . . 340 
 
 103. Sections of kame, Bennington Station, N. H. . . 341 
 
 104. Map of the kames of Maine. (Stone.). . 344 
 
 105. Section of burled kame, Hanover, N. H. (Upham.) . 345 
 
 106. Section of kame, Hanover, N. H. (Upham.) . 346 
 
 107. Buried kame, Stroudsburg, Pa. (Lewis and Wright.) .348 
 
 108. Canadian bowlder, Boone county, Ky. 368 
 
 109. Map showing the effect of the glacial dam at Cincinnati. (Claypole.) 369 
 
 110. Map of Paint Creek and Beech Flats, Ohio . • " 373 
 ill. Section of a deposit, Teazes Valley, W. Va. . . . 380 
 
 112. Split Rock, Boone county, Ky. ... 385 
 112a. Glacial map of Lake Cuyahoga. (Claypole.) . . 388 
 
 113. Section of the lake ridges near Sandusky, Ohio . . . 390 
 
 114. Map showing glacial lakelets In northern Ohio. (Claypole.) . . 396 
 
 115. Lake Whittlesey. (Leverett.) . . . . .399 
 
 116. Lake Warren. (Leverett.) . . . .399 
 
 117. Nlpisslng Great Lakes and Champlaln Sea . . . 399 
 
 118. Map of glacial lake, Erie-Ontario. (Claypole.) . 400 
 
 119. Stratified loess, Nebraska. (Chamberlln.) ^11 
 
 120. Gulley In the loess, Helena, Ark. (Crlder.) . 421 
 
 121. Polarprojeotlons . . ... 423 
 
 122. Map showing glaciated areas in North America and Europe facing 445 
 
 123. Glacial map of Europe . 456 
 
 124. Contorted drift of the Cromer ridge . 458 
 124a. Present and past glaciatlon of the Alps. (Leverett.) . . 460 
 
 125. Diagram showing eccentricity of the earth's orbit 466 
 
 126. Map showing Atlantic Ocean currents . . . 470 
 
 127. Map of July Isobars and prevailing winds . 471 
 
 128. Map of January Isobars and prevailing winds . 474 
 
 129. Glaciated pebble. (Coleman.) 493 
 
 130. Glaciated Pebble. (Coleman.) . 493 
 
 131. Glaciated Pleistocene siurface. (Coleman.) . 493 
 
 132. Bird's eye view of Niagara River. (Pohlman.) . . 536 
 
 133. Section of strata along the Niagara gorge . . .537 
 
 134. Map of the Niagara River below the falls . . . 538 
 
 135. Map showing recession of Hoiseshoe Falls since 1842 . . . 540 
 
 136. Exposure of Niagara shale In Niagara gorge. (Dutton.) . . 544 
 
 137. Diagram of mouth of Niagara gorge at Lewlston ... 544 
 
 138. Photograph looking northwest towards St. Davids . . 546 
 
 139. Section showing enlargement of Niagara gorge on east side at Its mouth 546 
 
 140. Hypothetic hydrography of the Great Lakes after the melting of the glacier from 
 
 the St. Lawrence Valley . . .547 
 
 141. Sections showing the actual rate of erosion along the sides of the Niagara 
 
 gorge . ..... . ... 551 
 
 142. Map of Mississippi River from Fort SnelUng to Minneapolis . . . .555 
 
 143. Ideal view of an unglaclated country. (Chamberlln.) 562 
 
 144. Ideal view of glaciated country. (Chamberlln.) . . . .563 
 
 145. Meanderlngs of Plum Creek through 6,000 feet of its trough . . . .564 
 
 146. Cross section of the new course of Plum Creek . . .... 564 
 
 147. Section of kettle-hole, Andover, Mass 572 
 
XX LIST OF ILLUSTRATIONS, 
 
 FIG. PAGE 
 
 148. Perpendicular section of till containing wood, Oxford, Ohio 57T 
 
 149. Part of Atlanta, Mo., topographic sheet . 589 
 
 150. Part of Oelweln, la., topographic sheet . • 589 
 
 151. Section of till overlying peat, Germantown, Ohio . • 593 
 
 152. Section of kettle-hole, Freehold, Pa. . . • 59S 
 
 153. Section In till containing wood, Darrtown, Butler county, Ohio . 599 
 
 154. Forest lately disturbed by an advancing Alaskan glacier.- (Gilbert.) 606 
 
 155. Map of the ancient lakes Bonneville and Lahontan. (Le Conte.) 608 
 
 156. Bowlder bed at Pocatello, Idaho • 615 
 
 157. Collection of palaeolithic implements 616 
 
 158. Reverse side of the same . 617 
 
 159. ArglUlte implemenc, Trenton, N. J. (10,985.) (Putnam.) . 626 
 
 160. Side view of the same. (Putnam.) ... 627 
 
 161. ArgUlIte implement, Trenton, N. J. (11,286.) (Putnam.) . 628 
 
 162. Black chert implement, Trenton. N. J. (10,986.) (Putnam.) 629 
 
 163. Section of Trenton gravel, N. J. (Abbott.) . . 631 
 
 164. Gravel deposit at Trenton, N. J., where human femur was found. (Records 
 
 of the Past.) . . ... 632 
 
 165. Ideal section on the Delaware River Valley, Trenton, N. J. (Abbott.) . ,633 
 
 166. Black chert implement, Madlsonville, Ohio. (40,970.) (Putnam.) . 642 
 
 167. Map showing glacial boundary, channels, and terraces near Cincinnati 643 
 
 168. Palseoliths from Newcomerstown and Amiens 645 
 
 169. Edge view of the same . . .647 
 
 170. Face view of implement from Brilliant, Ohio 64S 
 171*. Face view of same 64S 
 
 172. Diagonal view of same 648 
 
 173. Section of the trough of the Ohio at Brilliant 649 
 
 174. Gray flint Implement, Medora, Ind. (46,145.) (Putnam.) 650 
 
 175. Side view of the same. (Putnam.) 651 
 
 176. Section of gravel at Medora, Ind. 652 
 
 177. Chert implements, Morrison county, Minn. (Winchell.) 653 
 
 178. Quartz Implement, Little Falls, Minn. (31,323.) (Putnam.) 657 
 
 179. Quartz Implement, Little Falls, Mini. (31,316.) (Putnam.) 658 
 
 180. Ideal section. Little Falls, Minn. (Upham.) 660 
 
 181. Map of moraines in Minnesota. (Upham.) . . 662 
 
 182. Accumulating delta plain In front of Malasplna Glacier. (Russell.) . 667 
 
 183. Baltimore and Ohio Railroad cut, Claymont, Del. (Cresson.) 670 
 
 184. Nearer view of the same. (Cresson.) 672 
 
 185. Argllllte Implements from the preceding cut. (45,726.) (Putnam.) . 674 
 
 186. View showing Mr. Concannon's house and relation of the bluff to present 
 
 flood plain of the Missouri. (Records of the Past.) . 677 
 
 187. Geology of the Concannon Farm . 67& 
 
 188. Entrance to tunnel In which Lansing skelton was found. (Records of the 
 
 Past.) . . .680 
 
 189. Front view of skull and femur bones of Lansing skeleton. (Records of the 
 
 Past,) . .... . . 681 
 
 190. Side view of same. (Records of the Past.) . 681 
 
 191. Section of Long's Hill, Neb. (Records of the Past.) ... 684 
 
 192. Implement from Dag Hill. (Owen.) 
 
 193. Lava streams cut through by rivers in California. (Le Conte.) 
 
 194. Section across Table Mountain, Cal. (Le Conte.) . . . ... 689 
 
 195. McTarnahan mortar from under Table Mountain 697 
 
 196. Nampa figurine and map of the Snake River Valley 703 
 
LIST OF ILLUSTRATIONS. 
 
 XXI 
 
 Map showing the glacial geology o£ the United States and southern 
 
 Canada . between 134 and 135 
 
 Map showing the preglaclal drainage of the Great Lakes ' between 300 and 301 
 
 Map of the glacial Lake Agasslz facing 404 
 
 LIST OF PLATES. 
 
 PLATE 
 I. 
 II. 
 
 III. 
 
 IV. 
 
 V. 
 VI. 
 
 VII. 
 
 VIII. 
 IX 
 
 PAGE 
 
 facing 13 
 
 Sperry Glacier, Montana. (Sperry.) .... 
 
 Gelkie Glacier and Hanging Glacier, British Columbia. (Canadian 
 
 Topographical Survey.) . » . . facing 18 
 
 View of lUeciUewaet and Asulkan Glaciers, British Columbia. 
 
 (Wheeler.) . . facing 25 
 
 Forest on top of front of Malasplna Glacier, Alaska. (Russell. ) facing 33 
 
 Mulr Glacier In 1909 . between 74 and 75 
 
 North outcrop of Mammoth Bed overlaid by Kansan till, Morea, Fa. 
 
 (Williams.) facing 154 
 
 Topography of deep loess two miles south of margin of lowan drift, 
 
 northwest ol Iowa City, Iowa. (Todd.) . . facing 227 
 
 Stream of water along the margin of Malasplna Glacier. (Russell.) facing 320 
 Longitudinal kames near Hingham, Mass. (Bouv6.) " . . facing 340 
 
THE ICE AGE IN NORTH AMERICA. 
 
 CHAPTER I. 
 
 "WHAT IS A GLACIEE' 
 
 To the ordinary man of science, water is a mineral and 
 ice a rock ; but to the glacialist both are fluids. The appar- 
 ent solidity of ice is an illusion due to the dullness of our 
 senses. The reason why its viscous or semi-fluid character 
 remained unsuspected until a comparatively recent period is 
 due to -the fact that the ordinary movement of accessible 
 glaciers was so slow that we could not by observation readily 
 note their rate of progress. 
 
 The difference between water and other substances is 
 most noticeable in the phenomena connected with solidifi- 
 cation and fusing. Lead melts at 612° Fahr. above zero ; 
 sulphur, at 226° ; water, at 32° ; while mercury becomes 
 liquid at 39° below zero, and some other substances at even 
 lower temperatures. Thus, with reference to its fusing- 
 point, water appears toward the middle of the scale. If, 
 like the fabled salamander, man were able to endure intense 
 degrees of heat, he might, very likely, sustain relations to 
 iron similar to those he now sustains to water. He might 
 then bathe with pleasure in a molten flood, and venture on 
 the thin crust of a glowing mass of metal. 
 
 The suddenness with which water passes from the solid 
 to the liquid state, and the amount of heat absorbed in the 
 process of fusion, involve many important consequences. 
 Down to the freezing-point water may be made to part with 
 its heat by gradual stages, but in the act of freezing it sud- 
 
2 THE IGE AOE IN NORTH AMERICA. 
 
 denly gives out an enormous amount of heat ; on the con- 
 trary, when ice melts, a corresponding amount of heat is 
 absorbed in accomplishing the result. To melt a cubic foot 
 of ice requires as much heat as to raise a cubic foot of water 
 80° C. or 1M° Fahr. 
 
 For our knowledge of the nature of the movements tak- 
 ing place in glaciers, we are largely indebted to the investi- 
 gations of Louis Agassiz and Professor Forbes between the 
 years 1840 and 1842, and later to more detailed investigations 
 of Professor Tyndall and other physicists. The mode of 
 measurement with all these investigators was essentially the 
 same. Stakes were driven across a glacier in a line at right 
 angles to the direction of the movement ; and, by means of a 
 theodohte, accurate notations were taken, from hour to hour 
 and day to day, of any changes in the relative position of 
 the points where the stakes were driven. The uniform re- 
 sult of these observations was that the 
 line of stakes began immediately to curve 
 slowly down near the middle, showing 
 that the motion on the surface was greater 
 near the middle than on the sides. This 
 curve continued to increase as long as 
 the stakes remained standing. 
 
 Professor Tyndall's observations show 
 also that the most rapid line of motion 
 
 Fig. 1.— The letters o, 6, ■ , , . 
 
 c, d, «,/, g, represent ou the surfacB of a glacier IS not exactly 
 
 stakes driven across the " *' 
 
 snrface of a glacier, at m the middle : but that, wherever there 
 
 right angles to its Ime ^ ' ^ ' 
 
 of motion ; a', b', d jg a bend in the glacial current, the more 
 
 » I ^ . / , (7 ' represent ~ ' 
 
 subsequen't st^'e " * rapid movement is uniformly on the con- 
 vex side of the channel, so that the curve 
 of the line of most rapid motion is more tortuous than that 
 of the main channel. This conforms to the facts concerning 
 the movement of water in a crooked river-bed, and illustrates 
 again the analogy between the movement of ice and that of 
 water. 
 
 The most rapid motion observed by Tyndall, in the sum- 
 mer time, in the center of one of the largest of the Alpine 
 
 « Z c iC a f 3 
 
 o — o 0-.. o — (y-.-e— -o 
 
 -o.... 
 
 -o— <»—■ o--" 
 
 
WffAT IS A GLACIER f 
 
 3 
 
 glaciers, was thirty-seven inches per day. Near the sides of 
 
 the glacier, however, the movement was reduced to two or 
 
 three inches. The rate of motion during 
 
 the winter was only about one half that 
 
 during the summer. 
 
 A further resemblance of the motion of 
 
 a glacier to that of a river appears in the 
 
 fact that the ice near the top moves faster 
 
 than that near the bottom. At a point in 
 
 the Mer de Gluce where the side of the gla- 
 cier is exposed, presenting a wall of ice 
 
 about one hundred and fifty feet in height, 
 
 Professor Tyndall drove three stakes ; one 
 
 at the summit of the ice, another thirty-five 
 
 feet from the bottom, and another four feet 
 
 from the bottom. Upon examination of 
 
 them, at the end of twenty-four hours, it 
 
 appeared that, while the top stake had 
 
 moved forward six inches, the middle one 
 
 had moved but four and a half inches, and 
 
 the bottom stake but two and two thirds of 
 
 an inch. 
 
 In all these experiments the influence of friction is clearly 
 
 visible. The ice of the glacier is retarded by the friction of 
 
 the sides and bottom of 
 the channel through which 
 it moves, so that the most 
 rapid motion is upon the 
 surface, near the middle, 
 the part farthest removed 
 from this retarding influ- 
 ence. 
 A little attention to this last principle will prepare the 
 
 mind for crediting the observations which more recently 
 
 have been reported from the large glaciers in Greenland and 
 
 Alaska, showing a motion fifteen or twenty times that of 
 
 the Alpine glaciers. As the cross-section of a glacier is in- 
 
 Fig. 2.— The continu- 
 ous lines define the 
 valley occupied by 
 the glacier. The 
 dottea line with the 
 arrow - heads indi- 
 cates the line of 
 most rapid motion 
 in the ice, showing 
 its more sinuous 
 course. 
 
 Fig. 3. — a, b, c, are stakes driven in the vertical 
 wall of the side of a glacier ; a', b', c", are 
 the points occupied at a subsequent date. 
 
4 THE ICE AGE IN NORTH AMERICA. 
 
 creased, the relative influence of friction in retarding the 
 motion is rapidly diminished. The friction on the sides of 
 a glacier two miles wide is no greater than that upon one a 
 quarter of a mile in width, though the cross-section is eight 
 times as large. A cross-section of the Mer de Glace at Les 
 Moulins is estimated to be one hundred and ninety thousand 
 square yards ; whereas a cross-section of the Muir Glacier, in 
 Alaska, a mile above its mouth, is upward of one million 
 square yards. 
 
 Though observation shows that ice actually moves as if it 
 were a fluid, the scientific imagination is tasked to the litmost 
 to conceive how such motion can be consistent with other 
 manifest qualities of the material ; for in many conditions ice 
 seems as brittle as glass and as inelastic as granite. The 
 mystery is probably solved, so far as such questions are ever 
 solved, by attention to the facts already referred to concern- 
 ing the behavior of ice at its melting-point. When ice passes 
 into water, an immense amount of heat is absorbed in the 
 process, which yet does not produce any effect upon the 
 thermometer. If a hole be bored in the surface of a melting 
 glacier, and a thermometer inserted, it will stand at 32° Fahr. 
 If the same thermometer be inserted in the subglacial stream 
 issuing from the ice front, it will stand at the same point. 
 Yet the absolute difference between the heat contained in 
 the particles of ice, and that contained in the particles. of 
 water, is 144° Fahr.^so much heat being occupied in keep- 
 ing the substance in a liquid form. Ice is also transparent 
 to the rays of heat as it is to the rays of light. ' Scoresby 
 amused himiself, ■ in the arctic latitudes, by .making lenses of 
 ice with which to concentrate the sun's rays and set com. 
 bustible substances on fire. 
 
 The fusing-point of ice is also modified by pressure. 
 Under pressure the freezing-point of water may be lowered 
 two or three degrees ; but upon the removal of the pressure, 
 the water wiU instantly become solid. This has been demon- 
 strated in varioiis ways. M. Boussingault, for example, filled 
 a hollow steel cylinder with water, having a bullet loose with- 
 
WHAT IS A OLAGIERf g 
 
 in it, and plugged the aperture up. He then subjected the 
 cylinder to intense cold till the whole was two or three de- 
 grees below the freezing-point of water. But that the water 
 remained liquid was evident from the fact that, upon shaking 
 the cylinder, the bullet inside rattled about as at higher tem- 
 peratures; while, upon removing the plug so as to relieve 
 the pressure, the whole was instantly converted into solid 
 ice. Yarious similar experiments have been made in which, 
 upon removal of the plug, the water ejected from the aperture 
 by the expansive power of the cooling water within the 
 cylinder immediately freezes, and forms a projecting column 
 of ice several inches in length. It was at first thought that 
 this projecting column illustrated the plasticity of ice ; but 
 it is now pretty certain that it illustrates, rather, the curious 
 effect of pressure upon the freezing-point of water. 
 
 The capacity of water at the freezing-point to transform 
 itself, under varying degrees of pressure, from the solid to 
 the liquid state, and vice versa, is illustrated by another ex- 
 periment, ascribed by Professor Tyndall to Mr. Bottomley. 
 A' copper wire was looped over a bar of ice about four inches 
 square, and a weight of twelve or thirteen pounds was sus- 
 pended from it. The pressure under the wire caused the ice 
 in immediate contact with it to melt ; but, as the resulting 
 water escaped around the wire, and was relieved from press- 
 ure, it immediately froze, and cemented together again the 
 walls of ice above the wire. In half an hour the wire had 
 cut completely through the bar of ice, and yet the whole 
 breach above it was repaired, and the bar was intact. 
 
 This capacity of fragments of ice, when near the melting- 
 point, to freeze together when their faces are joined, can be 
 readily observed in a variety of experiments. When two 
 pieces of ice in a basin of warm water are brought together 
 they will immediately adhere. If a cake of ice whose tem- 
 perature is near the melting-point be placed in a mold and 
 subjected to pressure, the first result is to break it into pieces ; 
 but, on continuing the pressure, the particles reunite and 
 freeze together into a shape corresponding to that of the 
 
THE lOE AGE IN NORTH AMERICA. 
 
 mold. This capacity of ice, when near the melting-point, 
 to undergo disintegration, and then to become suddenly re- 
 
 T'^^^ 1%JW 
 
 Pig. 4. 
 
 -A, B, C, molds ; a, a, e, original forms of the ice ; S, d, f, the forms into which 
 they were molded. 
 
 congealed, is probably that by which it simulates in its mo- 
 tion the properties of ordinary fluids, while at the same time 
 retaining other properties connecting it with the most brittle 
 of substances. 
 
 It is thought, by Mr. Croll and others, that when heat 
 passes through a stratum of ice, as it is known to do, it involves 
 a process of transference from one particle of ice to another, 
 in which there are successive melting and freezing of the 
 particles in the progress of the heat, and that finally the mole- 
 cule of ice upon the opposite side, in becoming recongealefl, 
 delivers up the unit of heat which had entered the stratum 
 from the other side. But, whatever be the explanation of 
 the process, the facts remain that ice behaves in many re- 
 spects like a fluid, and, on application of pressure, slowly ad- 
 justs itself to its bed or mold in obedience to the force ap- 
 plied, and, if time enough is given, moves wherever a fluid 
 would find its way. Ice is plastic under pressure and brittle 
 under tension. 
 
 Snow is one form of ice, and, as every school-boy who 
 makes a snow-ball knows, can by a moderate degree of press- 
 ure be made into compact ice. The reason why snow is 
 white, and ice is blue, is that snow is pulverized, while in 
 ice the particles are brought into closer contact, and the 
 inclosed air is expelled, so that the real color of the substance 
 
WHAT IS A OLACIERf 7- 
 
 is brought out. TLe powder of almost any substance differs 
 in color from the compact mass. Glacial ice is compressed 
 snow, and originates wherever the snow-fall is largely in ex- 
 cess of the melting power of the sun and warm currents of air. 
 Any one can observe how much more compact old snow is 
 than new, and how, under pressure, the lower strata in a 
 snow-bank become in a single season almost like ice. Hence 
 it is easy to see what must be the result where the annual 
 snow-fall is never wholly melted away. In such regions the 
 ice would accumulate without limit, were it not for its semi- 
 fluid character, which permits it to flow off, in lines of least 
 resistance, to lower levels and toward warmer climes. 
 
 In structure glacial ice is characterized by both vems and 
 fissures — two phenomena, which are produced by opposite 
 causes — the first by pressure, and the second by tension. 
 
 Glacial ice ordinarily presents a vemed structure. Instead 
 of being homogeneous, it consists of alternate bands of light- 
 colored and blue ice. These bands do not, however, lie in a 
 horizontal position, but are often vertical. Sometimes they 
 run parallel with the movement of the glacier, and sometimes 
 at right angles to the motion ; while, at other times, they are 
 arranged at an angle of forty-five degrees, pointing down the 
 line of motion. From close examination it appears that the 
 veins are always at right angles to the line of greatest pressure. 
 
 For example, where two branches of a glacier join, and 
 press together from the sides, longitudinal veins are produced 
 below the point of junction. And again, where ice has de- 
 scended a declivity, and is advancing upon a less inclined 
 plane, the increased pressure necessary to push the mass along 
 produces bands at right angles to the line of motion ; thus 
 demonstrating the connection of veins with pressure. The 
 theory is, that the blue veins in the ice are those from which 
 pressure has expelled the particles of air, thus making it 
 more compact, and giving it its blue color. As already re- 
 marked, snow is white because of the abundant particles of 
 air inclosed within it. Under pressure it can be transformed 
 into blue ice, corresponding to the blue veins alluded to. 
 4 
 
THE IGE AGE IN NORTH AMESICA. 
 
 An active glacier is also characterized \>j fissures. When- 
 ever the ice-stream reaches a point where its slope is increased 
 even by a very small amount (a change in inclination of two 
 degrees being sufficient), the ice instead of moving in a con- 
 tinuous stream, forms crevasses across the current, which 
 gradually enlarge at the top, until they present a series of 
 long chasms, very difficult for the explorer to traverse. 
 Where there is considerable irregularity in the bottom, and 
 the increased slops extends for some distance, these crevasses 
 become very complicated, and the surface presents an ex- 
 panse of towers and domes and pinnacles of ice, often of fan- 
 tastic appearance ; 
 but at the bottom 
 these masses are 
 still joined, and on 
 coming down to a 
 gentler slope they 
 close up again at 
 
 Fig. 5.— c, c, show fissures and seracB where the glacier moves the SUrface for 
 down the steeper portion of its incline ; s, «, show the v, ivy 
 
 vertical stmctare produced by pressure on the gentler their Onward 
 
 march. 
 In addition to the crevasses or iissures, produced by the 
 tension where the ice-stream passes over a steeper incline, a 
 set of marginal iissures extend from the sides of the glacier 
 toward the center, but pointing upward at an angle of about 
 forty-five degi-ees. These, 
 
 \' 
 
 x 
 
 t 5« 
 
 too, appear to be the result 
 of tension. The motion of 
 the ice in the center, being 
 more rapid than that to- 
 ward' the sides, produces a 
 line of tension, or strain, ex- 
 tending from the center di- 
 agonally downward toward 
 the sides at an angle of 
 forty-tive degrees. The pressure upon these masses of ice^ 
 whose central point is being wheeled downward by the differ 
 
 Fig, 6. 
 
 Fig. \ 
 
 Fios. 6, 7.— Illustrate the formation of margin- 
 al fissures and veins. 
 
WHAT JS A GLACIERS 
 
 9 
 
 ential motion, produces also a veined structure in the masses 
 themselves, at right angles to these marginal iissures. 
 
 The surface of a glacier presents many interesting phe- 
 nomena. When the ice-stream is of sufficient size, the sur- 
 face is covered with a network of 
 small streams of water, flowing through 
 blue channels of ice sometimes many 
 yards in depth and width. But these 
 are destined eventually to encounter 
 some crevasse,. where a circular shaft, 
 or moulin, as it is called, is formed, 
 opening a way to a subglacial chan- 
 nel, into which the streams plunge nu. 8.-Eiiistrate8 the foima- 
 
 . .-1 1 J J .1 1,1 tion ol veined structure by 
 
 witn a loud roar, and the accumulated pressure at the juDction of 
 
 , _e. 1 1 T 1 . two branches. 
 
 waters may often be heard rushmg 
 
 onward hundreds of feet below the surface. During the 
 melting of a glacier, also, in the summer season, the surface 
 of the ice is frequently dotted vrith bowl-shaped depressions, 
 from one or two inches to many feet in depth, and filled 
 with beautiful clear water. The cause of this can not well 
 be conjectured. In Greenland, Nordenskiold attributed the 
 initial melting to accumulations of meteoric dust which he 
 named kryokonite. 
 
 Glaciers in mountainous regions are also characterized by 
 lateral and medial moraines. Where the ice stream passes 
 by a mountain-peak, the falling rocks and the avalanches 
 started by streams of water, form along the edge of the gla- 
 cier a continuous line of debris, which is carried forward by 
 the moving ice, and constitutes what is called a lateral mo- 
 raine. If there be a current of ice on each side of the mount- 
 ain-peak, two of the lateral moraines will become joined be- 
 low the mountain, and will form what is called a medial 
 moraine, which will be carried along the back of the ice as 
 far as the motion contiimes. As the ice wastes away toward 
 the front, several medial moraines sometimes coalesce. This, 
 as will be seen, is finely shown in some glaciers of Alaska. 
 
 A medial moraine, when of sufficient thickness, protects 
 
10 
 
 THE ICE AOE JN NORTH AMERICA. 
 
 the ice underneath it from melting; so that the moraine 
 
 will often appear to be much larger than it really is : what 
 
 seems to be a ridge of earthy material 
 
 being in reality a long ridge of ice, thinly 
 
 covered with earthy debris, sliding down 
 
 the slanting sides as the ice slowly wastes 
 
 away. Large blocks of stone in the same 
 
 manner protect the ice from melting un- 
 
 FirTlModeoffo^ion dcmeath, and are found standing on pe- 
 of ice-pillars. ^^^^^^ ^^ j^.^^ ^^^^^ ^^^ general surface 
 
 has been lowered sometimes several feet. An interesting 
 feature of these blocks is that when the pedestal fails, the 
 block uniformly falls to- 
 ward the sun, since that 
 is the side on which the 
 melting has proceeded 
 most rapidly. 
 
 All the material 
 brought down upon the 
 surface of the glacier in 
 the medial moraines is 
 deposited at the front, 
 forming a terminal mo- 
 raine, which will vary in 
 size according to the 
 abundance of material 
 transported by the ice, 
 and in proportion to the 
 length of time during 
 which the front rests at 
 a particular point. But, 
 ordinarily, for a consid- 
 erable distance this mo- 
 raine material near the 
 front will rest upon ex- 
 tensive masses of ice '^'■^^fZ.^'^^^v ^l^rir''^^Z.t 11'. 
 
 which only slowly melt lSX?d"e^'lU'&Sl^1^o'?a1n1'abovl°^ 
 
WHAT IS A OLACIEBt H 
 
 away. It is largely owing to this that a true terminal 
 moraine is made up of knolls and bowl-shaped depressions 
 called kettle-holes, and of short tortuous ridges of bowlders 
 and gravel. 
 
 Another result connected with the decay of a glacier is 
 the production of kames — this being the Scotch word for 
 sharp, narrow ridges of gravel, corresponding to what are 
 called osars in Sweden and eskers in Ireland. The trend of 
 these ridges is the same as that of the motion of the glacier, 
 and is at right angles to tlie terminal moraine. Their for- 
 mation can be witnessed on a large scale near the front of 
 the Muir Glacier in Alaska. In certain localities a great 
 amount of sand, gravel, and bowlders becomes spread out 
 over the surface of the ice at a considerable elevation. 
 Through some changes in the subglacial drainage a stream 
 wears a long tunnel in the ice underneath this deposit, 
 which at length proceeds so far that the roof caves in, and 
 the earthy debris is gradually precipitated to the bottom 
 of the tunnel, thus forming one class of kames. In other 
 places, evidently, water-worn channels in the ice have been 
 silted up by the' stream, and then the line f)f drainage 
 changed, so that, when the supporting walls of ice melted 
 away, another class of kames, with what is called " anticli- 
 nal " stratiiieation, is produced. 
 
 It should be mentioned also that, after the analogj' of a 
 river, a glacier shoves sand and gravel and bowlders under- 
 neath it along its bed'; from which it can easily be seen that 
 a glacier is a powerful eroding agency, rasping down the 
 surface over which it moves, and by the iirm grasp in which 
 it holds the sand, gravel, and bowlders underneath it, pro- 
 ducing grooves and scratches and polished surfaces on the 
 rocks below, while these stones themselves will in turn be 
 scratched and polished in a peculiar manner. Wherever the 
 glaciers have receded, so that their bed can be examined, 
 these phenomena, which we reason from the nature of the 
 ease must have been produced, are found actually to occur, 
 and a terminal moraine is sure to contain many pebbles and 
 
12 
 
 THE ICE AGE IN NORTH AMERICA. 
 
 bowlders bearing marks of the peculiar attrition to wliich 
 they have been subjected in their motion underneath the 
 ice. The rocks brought along upon the surface of the gla- 
 cier of course are not thus striated, and ordinarily the mate- 
 
 FlG. 11.— Glacial scorings (aftL-r Agassiz). 
 
 rial of the kames has been so much rolled by water that if 
 the pebbles ever were scratched, the marks have been erased. 
 With this brief account of the physical characteristics of 
 ice, and of the effects produced by its movement in a gla- 
 cier, we are prepared to enter more understaudingly upon a 
 survey of the actual facts relating to the past and present 
 extent of the ice-fields over the northern part of ITorth 
 America. Heserving the discussion of theories concerning 
 the cause and date of the glacial period to the latter part of 
 the treatise, we will first consider the facts concerning the 
 glaciers still existing in America, and then briefly, by way of 
 comparison, those concerning glaciers in other portions of 
 the world ; after which we will present in considerable 
 detail the more recent discoveries concerning the extension 
 and work of the great American ice-sheet during the so- 
 called Glacial period. 
 
r" 
 
CHAPTER II. 
 
 GLACIERS ON THE PACIFIC COAST. 
 
 Notwithstanding the great height of the Rocky Moun- 
 tains, they are, in the southern part, devoid of living glaciers. 
 This lack is doubtless caused by the dryness of the atmos- 
 phere, the winds from the Pacific having already, before 
 reaching the interior, yielded their moisture to the solicita- 
 tions of the lofty peaks of the Sierra Nevada and the Cascade 
 Range. Still, a few small glaciers are found among the sum- 
 mits of the Wind River Mountains of Wyoming, and near the 
 sources of Flathead River in Montana. Farther north, how- 
 ever, near the Canadian boundary, glaciers begin to appear 
 in increasing number and size. The broad picturesque sum- 
 mits of the Rocky Mountains forming the continental divide 
 between the head-waters of the Flathead River in Montana 
 and those of the Belly, a branch of the Saskatchewan, in 
 Canada, support innumerable glaciers of small size and many 
 that compare well with those of the Alps. More than forty 
 are found between Lake McDonald and the Canadian bound- 
 ary. Of these the Sperry and Chaney glaciers are most 
 conspicuous. Avalanche Lake, surrounded by glacier-cov- 
 ered peaks, is one of the most picturesque localities on the 
 continent. 
 
 In the Canadian Rockies and in the Selkirk Mountains, 
 north of the line, in Alberta and British Columbia, glaciers 
 increase in numbers and size as higher latitudes are reached. 
 Of these the Victoria, the Wenkchemna, the Yoho, thelllecille- 
 waet and the Asulkan are so near stations on the Canadian 
 
14 
 
 THE ICE AGE IN NORTH AMERICA. 
 
 Pacific Railroad that they can be easily visited by tourists. 
 The snow-fields of all these are from 9,000 to 10,000 feet above 
 sea-level, but none of the glaciers descend much below 6,000 
 feet, except the lUecillewaet which reaches the level of 4,800 
 feet. 
 
 Fig. 12.— West end of Samovar Glacier. Alaska . 
 
 A wide arid space, of which few who have not traversed 
 the region can have any conception, separates the Rocky 
 Mountains from the Sierra Nevada nearer the Pacific coast. 
 This latter range of mountains is, in some respects, favorably 
 situated for the production of glaciers, since the peaks are 
 lofty, rising in many places upward of 14,000 feet, and there 
 is abundance of snowfall. Ordinarily, however, there is not 
 breadth enough to the summit of the range to furnish ade- 
 quate snow-fields for the production of first-class glaciers. 
 
 The most southern collection of glaciers in the Sierra 
 Nevada is found near the thirty-seventh parallel, a little 
 east of the Yosemite Valley, in Tuolumne and Mono coun- 
 ties, California. Here is a remarkable cluster of mount- 
 
GLACIERS ON THE PACIFIC COAST. 15 
 
 ain-peaks rising upward of 14,000 feet above the sea, and 
 with breadth enough to support numerous snow-fields and 
 glaciers. No less than sixteen glaciers of small size have 
 been noted among these summits, of which those on Mount 
 Dana, Mount Lyell, and in Parker Creek are the principal. 
 None of them, however, are of great size, being in no case 
 over a mile in length, and none of them descending much 
 below the 11,000-foot line.* 
 
 The continuation of the Sierra Nevada Mountains to the 
 north of California is called the Cascade Range, and is largely 
 composed of volcanic rocks. It is on Mount Shasta, in the 
 extreme northern portion of California, that we next find 
 glaciers of any considerable size. But from this point on, 
 glaciers multiply and continue, in ever-increasing glory, 
 through the Coast Range of British Columbia and southern 
 Alaska to the islands of the Aleutian Archipelago. 
 
 The glaciers upon Mount Shasta were first described by 
 Mr. Clarence King in 1870. Previous explorers had as- 
 cended the mountain upon the southern side, and reported it 
 as free from glaciers, which are all upon the northern side. 
 The most recent and detailed account of the glaciers on this 
 mountain has been furnished by Mr. Gilbert Thompson, of 
 the United States Geological Survey .f According to Thomp- 
 son, Mount Shasta is a volcanic peak whose altitude above 
 the sea is 14,511 feet. " It stands alone and has no connec- 
 tion with neighboring mountains, none of which within a 
 radius of forty miles attain two thirds its height." The 
 mountain is a conspicuous object to attract attention for 
 over a hundred miles. Five glaciers have been explored 
 upon its northern flank, none of them, however, reaching 
 lower than the 8,000-foot level, and none being more than 
 three miles in length. 
 
 The lower part of these glaciers is covered with vast 
 quantities of earthy debris, so? that it is difficult to teU where 
 the ice-field now ends. It was from these half-buried edges 
 
 * Russell, " Existing Glaciers," pp. 310-327. f ^^id., pp. 332-3.S4. 
 
Ifi TEE ICE AGE IN NORTE AMERICA. 
 
 of the ice-front on the flanks of Shasta that Mr. King drew 
 the analogies which first solved the problem of the irregular 
 gravel deposits forming the so-called kames and kettle-holes 
 in JSTew England, as above described.* Mr. King gives a 
 thrilling account of how he at one time started such a move- 
 ment of earth into one of tlie ice-tunnels, and came near 
 himself falling into the yawning ice-chasm.f 
 
 The following are the principal portions of Mr. King's 
 clear and vivid description of the glaciers on the north side 
 of Mount Shasta : 
 
 We reached the rim of the cone, and looked down into a 
 deep gorge lying between the secondary crater and the main 
 mass of Shasta, and saw directly beneath us a fine glacier, 
 which started almost at the very crest of the main mountain, 
 flowing toward us, and curving around the circular base of 
 our cone. Its entire length in view was not less than three 
 railes, its width opposite our station about four thousand feet, 
 the surface here and there terribly broken in "cascades," and 
 presenting all the characteristic features of similar glaciers else- 
 where. The region of the terminal moraine was more extended 
 than is usual in the Alps. The piles of rubbish superimposed 
 upon the end of the ice indicated a much greater thickness of 
 the glacier in former days. After finishing our observations 
 upon the side crater, and spending a night upon the sharp 
 edge of its rim, on the following morning we climbed over 
 the divide to the main cone, and up the extreme summit of 
 Shasta. . . . From the crest I walked out to the northern edge 
 of a prominent spur, and looked down upon the system of 
 three considerable glaciers, the largest about four and a half 
 miles in length, J and two to three miles wide. On the next 
 day we descended upon the south side of the cone, following 
 the ordinary track by which earlier parties have made the 
 climb. Prom the moment we left the summit we encountered 
 
 * Russell, "Existing Glaciers," p. 11. 
 
 f "Proceedings of the Boston Society of Natural History," vol. xix, p. 61. 
 
 X These estimates prove to be somewhat exaggerated. Thompson gives the 
 length of the Whitney Glacier, the longest on the mountain, as only 3,800 yards, 
 leas than two miles and a half. 
 
J 8 THE ICE AGE IN NORTH AMERICA. 
 
 less and less snow, and at no part of the journey were able to 
 see a glacier. An east-and-west line divides the mountain 
 into glacier-bearing and non-glacier-bearing halves. The as- 
 cent was formerly always made upon the south side, where, 
 as stated, there are no glaciers, and this is why able scientific 
 observers like Professor Whitney and his party should have 
 scaled the mountain without discovering their existence. . . . 
 Upon reaching the eastern side we found in a deep caflon 
 a considerable glacier, having its origin in a broad n6v6 which 
 reaches to the very summit of the peak. The entire angle 
 of this glacier can be hardly less than twenty-eight degrees. 
 It is one series of cascades, the whole front of the ice being 
 crevassed in the most interesting manner. Near the lower end, 
 divided by a boss of lava, it forks into two distinct bodies, one 
 ending in an abrupt rounded face no less than nine hundred 
 feet in height. Below this the other branch extends down 
 the caflion for a mile and a half, covered throughout almost 
 this entire length with loads of stones which are constantly fall- 
 ing in showers from the cafion-walls on either side. Indeed, 
 for a full mile the ice is only visible in occasional spots, where 
 cavities have been melted into its body and loads of stones 
 have fallen in. From an archway under the end a consider- 
 able stream flows out, milky, like the water of the Swiss 
 glacier-streams, with suspended sand. Following around the 
 eastern base of Shasta, we made our camps near the upper 
 region of vegetation, where the forest and perpetual snow touch 
 each other. A third glacier, of somewhat greater extent than 
 the one just described, was found upon the northeast slope of 
 the mountain, and upon the north slope one of much greater 
 dimensions. The exploration of this latter proved of very 
 great interest in more ways than one. Eeceiving the snows 
 of the entire north slope of the cone, it falls in a great field, 
 covering the slope of the mountain for a breadth of about 
 three or four miles, reaching down the caflons between four and 
 five miles, its lower edge dividing into a number of lesser ice- 
 streams which occupy the beds of the caflons. This mass is 
 sufficiently large to partake of the convexity of the cone, and, 
 judging from the depth of the caflons upon the south and 
 southeast slopes of the mountain, the thickness can not be less 
 
Pi.ATE II — Geikle Glaoior and Hano;inG; Glacier on Mounts Fox and Dawson . Rriti: 
 Golumbia. fPhofo by Canadian Topographical Survey.) 
 
GLACIERS ON THE PACIFIC COAST. 19 
 
 than from eighteen to twenty-five hundred feet. It is cre- 
 vassed in a series of immense chasms, some of them two thou- 
 sand feet long by thirty and even fifty feet wide. In one or 
 two places the whole surface is broken with concentric systems 
 of fissures, and these are invaded by a set of radial breaks 
 which shatter the ice into a confusion of immense blocks. 
 Snow-bridges similar to those in the Swiss glaciers are the 
 only means of crossing these chasms, and lend a spice of 
 danger to the whole examination. The region of the terminal 
 moraines is quite unlike that of the Alps, a larger portion of 
 the glacier itself being covered by loads of angular debris. 
 The whole north face of the mountain is one great body of 
 ice, interrupted by a few sharp lava-ridges which project 
 above its general level. The veins of blue ice, the planes of 
 stratification, were distinctly observed, but neither moulins 
 nor regular dirt-bands are present. Numerous streams, how- 
 ever, flow over the surface of the ice, but they happen to pour 
 into crevasses which are at present quite wide.* 
 
 From Mount Shasta to the Columbia River the moun- 
 tains support many glaciers of the third order. Mount Jef- 
 ferson, Diamond Peak, and the Three Sisters are reported 
 by Mr. Diller and Professor Newberry as containing numer- 
 ous glaciers, and "as affording the most interesting field for 
 glacial studies in the United States, with the exception of 
 Alaska." The glaciers upon Mount Hood have been more 
 fully explored, and aire of great interest, though, owing to 
 the moderate elevation (11,000 feet) and the li,mited snow- 
 fields, they are small in size. The summit of this mountain 
 is occupied by a volcanic crater about half a milte in diameter. 
 This serves as a fountain out of which there flow three 
 streams of ice extending down the flanks, as glaciers, for a 
 distance of about two miles, their subglacial streams form- 
 ing the head-waters of the White Sandy, and the Little 
 Sandy Rivers. 
 
 In the State of Washington, a short distance north of the 
 Columbia River, the Cascade Mountains culminate in a clus- 
 
 * "American Journal of Science," vol. ci, 1871, pp. 158-161. 
 
GLACIERS ON THE PACIFIC COAST. 
 
 21 
 
 ter of peaks, with Mount Rainier, or, as it is conung to be 
 called, Tauoiiia, as the center. This central peak is upward 
 of 14,4-01) feet in height, and two or three neighboring peaks 
 are upward of 10,000 feet. This great elevation, coupled 
 with the higher latitude and rhe increasing moisture of the 
 climate, favors the production of a most imposing series of 
 glaciers. Even the passing traveler upon the railroad is 
 made aware of their existence by the milky whiteness of the 
 waters of the Cowlitz, the Xisqually, the Puyallup, and the 
 White River, which are crossed on the way from Portland, 
 Oregon, to Seattle in the State of Washington. All of these 
 streams originate in glaciers far up on the flanks of the 
 mountains to the east and south. 
 
 Of this series, that on the north side of Mount Taeo- 
 ma, at the head of White liiver Valley, is the largest, and 
 
 Fig. 15.— Mount Tacoma, looking eaBtward toward the summit, from Crattr Lake. 
 
 reaches down to within .5,000 feet of the sea-level. This 
 glacier is about ten miles long, and, though comparatively 
 narrow in its lower portion, is in places as much as four 
 miles wide. The extreme summit of the mountain has been 
 ascended only hy two or three parties, and the task is beset 
 with such difficulties that it is not likely to be ascended 
 often. Above the 9,000-foot level it is wholly enveloped in 
 snow ; while just below that limit, and close up to the realm 
 of perpetual ice and snow, flowers make the air fragrant witli 
 
22 THE ICE AGE IN NORTH AMERICA. 
 
 their perfume, and the open spaces are gorgeous with their 
 masses of brilliant color. 
 
 The following is the description of tlie glaciers of this 
 mountain cluster, as given by Mr. S. F. Emmons, of the 
 United States Geological Survey, the first to ascend it : 
 
 The main White River glacier, the grandest of the whole, 
 pours straight down from the rim of the crater in a northeast- 
 erly direction, and pushes its extremity farther out into the 
 valley than any of the others. Its greatest width on the steep 
 slope of the mountain must be four or five miles, narrowing 
 toward its extremity to about a mile and a half ; its length can 
 be scarcely less than ten miles. The great eroding power of 
 glacial ice is strikinglyillustrated in this glacier, which seems 
 to have cut down and carried away, on the northeastern side 
 of the mountain, fully a third of its mass. The thickness of 
 rock cut away — as shown by the walls on either side — and the 
 isolated peak at the head of the triangular spur . . . may be 
 roughly estimated at somewhat over a mile. Of the thick- 
 ness of the ice of the glacier I have no data for making esti- 
 mates, though it may probably be reckoned in thousands of feet. 
 
 It has two principal medial moraines, which, where crossed 
 by ns, formed. little mountain-ridges, having peaks nearly one 
 hundred feet high. The sources of these moraines are cliffs 
 on the steeper mountain-slope, which seem mere black specks 
 in the great white field above ; between these are great cas- 
 cades, and below, immense transverse crevasses, which we had 
 no time or means to visit. The surface water flows in rills 
 and brooks on the lower portion of the glacier, and moulins 
 are of frequent occurrence. We visited one double moulin, 
 where two brooks poured into two circular wells, each about 
 ten leet in diameter. Joined together at the surface but sepa- 
 rated below ; we could not approach near enough the edge to 
 see the bottom of either, but, as stones thrown in sent back 
 no sound, judged they must be very deep. 
 
 This glacier forks near the foot of the steeper mountain- 
 slope, and sends off a branch to the northward, which forms a 
 large stream flowing down to join the main stream fifteen or 
 twenty miles below. Looking down on this from a high, over- 
 
GLACIERS ON THE PAGIFIG COAST. 23 
 
 hanging peak, we could see, as it were, under our feet, a little 
 lake of deep, blue water, about an eighth of a mile in diameter, 
 standing in the brown, gravel-covered ice of the end of the 
 glacier. On the back of tlie rocky spur which divides these 
 two glaciers, a secondary glacier has scooped out a basin-shaped 
 bed, and sends down an ice-stream, having all the characteris- 
 tics of a true glacier, but its ice disappears several miles above 
 the mouths of the large glaciers on either side. Were nothing 
 known of the movement of glaciers, an instance like this would 
 seem to afEord suflBcient evidence that such movement exists, 
 and that gravity is the main motive-power. From our north- 
 ern and southern points we could trace the beds of several large 
 glaciers to the west of us, whose upper and lower portions only 
 were visible, the main body of the ice lying hidden by the high 
 intervening spurs. 
 
 Ten large glaciers observed by us, and at least half as 
 many more hidden by the mountain from our view, proceeding 
 thus from an isolated peak, form a most remarkable system, 
 and one worthy of a careful and detailed study.* 
 
 Still farther to the north, in the State of Washington, 
 Mount Baker, rising to an elevation of 11,000 feet, is to a 
 limited extent a center for the dispersion of glaciers of small 
 size. The field, however, has been but imperfectly explored. 
 
 Northward from the State of Washington the coast is 
 everywhere very rugged, being formed by the lofty peaks of 
 an extension of the Cascade Range; while the thousands of 
 islands which fringe the coast of British Columbia and Alaska 
 are but the partially submerged peaks of an extension of the 
 Coast Range, from which the great glaciers of former times 
 have scraped off nearly all the fertile soil. It is estimated 
 that there are ten thousand islands between the State of 
 Washington and Mount St. Ellas, and all the larger of them 
 bear snow-covered summits during the whole year. The water 
 in the narrow channels separating these islands is ordinarilj' 
 several hundred feet deep, affording, through nearly the 
 whole distance, a protected channel for navigation. 
 
 * Quoted by Clarence King, in the "American Journal of Science," 
 vol. ci, pp. 164, 165. 
 
t.SimpBon 
 Fig. 16.— Map of Southeastern Alaska. The arrow-points mark gJaciew. 
 
GLACIERS ON TEE PACIFIC COAST. 25 
 
 Three great rivers interrupt the mountain barrier of 
 British Columbia facing the Pacific— the Fraser, the Skeena, 
 and the Stickeen — and the interior is penetrated for some 
 distance by innumerable fiords. The Canadian Pacific Kail- 
 road follows the course of the Fraser for a long distance, and 
 passes within sight of glaciers of considerable extent, and 
 every fiord receives the drainage of numerous decaying gla- 
 ciers. But it is not until reaching the Stickeen Eiver, in 
 Alaska, in latitude 57°, that glaciers begin to appear which 
 are both easily accessible and large enough to invite pro- 
 tracted study. The water coming into the soimd from the 
 Stickeen Eiver is heavily charged with glacial mud, which 
 spreads itself out over a great expanse. An extensive delta, 
 forming almost the only arable land in southeastern Alaska, 
 has been built up by the deposit at the mouth of this river. 
 The earhest accurate information obtained concerning these 
 glaciers is that gathered by Mr. William P. Blake in 1863. 
 According to him, " there are four large glaciers and several 
 smaller ones visible within a distance of sixty or seventy miles 
 from the mouth" of the river. The second of these larger 
 ones has attracted most attention. This "sweeps grandly 
 out into the valley from an opening between high mountains 
 from a source that is not visible. It ends at the level of the 
 river in an irregular bluff of ice, a mile and a half or two 
 miles in length, and about one hundred and fifty feet high. 
 Two or more terminal moraines protect it from the direct 
 action of the stream. What at first appeared as a range of 
 ordinary hills along the river, proved on landing to be an 
 ancient terminal moraine, crescent-shaped, and covered with 
 a forest. It extends the fuU length of the front of the 
 glacier." * 
 
 This glacier presents many difficulties to explorers. A 
 small party of Russian officers once attempted its explora- 
 tion, and were never heard from again. Mr. Blake re- 
 ports that, as usual with receding glaciers, a considerable 
 
 * "American Journal of Science," vol. xoiv, 1867, pp. 96-101. 
 
GLACIERS Oy THE PACIFIC COAST. 27 
 
 portion of the front as it spreads out in the valley is so cov- 
 ered with bowlders, gravel, and mud that it is difficult to tell 
 where the glacier really ends. But from the valley to the 
 higher land it rises in precipitous, irregular, stair-like blocks, 
 with smooth sides, and so large that it was impossible to sur- 
 mount them with the ordinary equipment of explorers. The 
 glacier is estimated to be about forty miles long. 
 
 Another glacier, upon the opposite side of tie river, of 
 which Mr. Blake does not speak, was reported to me by those 
 familiar with the country as coming down to within about 
 two miles of the bank. The Indians are very likely correct 
 in asserting that these two glaciers formerly met, compelling 
 the Stickeen River to find its way to the sea through a vast 
 tunnel. It would then have appeared simply as a subglacial 
 stream of great magnitude. 
 
 North of the Stickeen River, glaciers of great size are of 
 increasing frequency, and can be seen to good advantage 
 from the excm-sion-steamer. The Auk and Patterson gla- 
 ciers appear first, not far north of Fort Wrangel. On 
 approaching Holkham Bay and Taku Inlet, about latitude 
 58°, the summer tourist has, in the numerous icebergs en- 
 countered, pleasing evidence of the proximity of still greater 
 glaciers coming down to the sea-level. Indeed, the glaciers 
 of Taku Inlet are second only in interest to those of Glacier 
 Bay, hereafter to be described more fully. 
 
 In going from Juneau to ChUkat, at the head of Lynn 
 Canal, a distance of about eighty miles, nineteen glaciers of 
 large size are in full sight from the steamer's deck, but 
 none of them come down far enough to break off into the 
 water and give birth to icebergs. The Davidson Glacier, 
 however, conies down just to the water's edge, and has there 
 built up an immense terminal moraine all along its front. 
 
 An illustration of the precipitous character of the south- 
 eastern coast of Alaska is seen in the fact that it is only 
 thirty-five miles from the head of Lynn Canal to the sources 
 of the Yukon River, which then fiows to the north and west 
 for nearly three thousand miles before coming down to the sea- 
 
OLAGIERS ON THE PACIFIC COAST. 29 
 
 level. Lieutenant Schwatka reports four glaciers of consider- 
 able size in the course of this short portage between Chilkat 
 and Lake Lindeman.* The vast region through which the 
 Yukon flows to the north of these mountains is not known 
 to contain any extensive glaciers. But the ground remaius 
 perpetually frozen at a short depth below the surface. Russell 
 reports that in many places cliffs of ice abut upon the border 
 of the Yukon on whose surface is a sufficient depth of soil 
 
 Fig. 19. — Davidson Glacier, near Chilkat, Alaska, latitude 59° 45'. Tlie mountains are 
 from five thousand to seven thousand feet high ; the gorge about three quarters of 
 a mile wide ; the front of the glacier, three mUes ; the terminal moraine, about two 
 hundred and fifty feet high. (View from two miles distant.) 
 
 to support dense evergreen forests. Since the discovery of 
 gold in the region a considerable population has entered, and 
 certain forms of agriculture have begun to flourish. 
 
 From Cross Sound, about latitude 58° and longitude 136° 
 west from Greenwich, to the Alaskan Peninsula, the coast is 
 bordered by a most magnificent semicircle of mountains, 
 opening to the south, and extending for more than a thousand 
 miles. Throughout this whole extent, glaciers of large size 
 
 * " Science," vol. iii (February 22, 1884), pp. 220-227. 
 
30 THE ICE AGE IN NORTH AMERICA. 
 
 are everywhere to be seen. Elliott estimates that, count- 
 ing great and small, there can not be less than five thousand 
 glaciers between Dixon's Entrance and the extremity of the 
 Alaskan Peninsula. 
 
 The glaciers in the vicinity of Mt. St. Ellas are the largest 
 anywhere to be found on the continent. Nxmierous single 
 glaciers, of which Seward is the largest, come down from the 
 mountain range and, becoming confluent, unite to form the 
 Malaspina glacier. This is a plateau of ice about 1,500 feet 
 in height stretching all along the southern base of the St. 
 Elias range for a distance of fifty miles, and covering an 
 area of about a thousand square miles. In Icy Bay the gla- 
 cier comes down to sea-level, presenting a solid wall many 
 miles in extent, which is continually breaking off into ice- 
 bergs of great size. Far out upon the surf ace large forests 
 occur surrounded by glacial ice. These are supported upon 
 deep beds of gravel and sand which have been carried out by 
 mountain streams whose channels have changed from time 
 to time with the varying conditions of the surface of the ice. 
 Lakes of considerable size are also found upon the surface 
 at an altitude as high as 5,000 feet, with streams flowing 
 between the ice and the mountain side, illustrating, possibly, 
 the origin of many terraces of gravel on the flanks of moun- 
 tains in the glaciated region of the United States. Such are 
 to be noted on the flanks of both the Green and the Adiron- 
 dack mountains, deposited originally on the sides of the mass 
 of ice that filled the Champlain Valley. 
 
 The glaciers of the St. Elias range are, however, mostly 
 confined to the south side which is exposed to the sea breezes. 
 Schwatka and Hayes who in 1892 made the tour of the 
 range, coming out at Copper River, found the country free 
 from glaciers and the climate so dry that they could comfort- 
 ably sleep out of doors. 
 
 The glaciers about the upper end of YaJsutat Bay are of 
 special interest because of the recent changes which have 
 
GLACIERS ON THE PACIFIC COAST. 
 
 31 
 
 taken place in them. The narrowing upper portion of the 
 bay which is now bordered by the gravel deposits of the gla- 
 cial streams pouring out from the southeastern portion of 
 the Malaspina Glacier is called Disenchantment Bay. But 
 above Haenke Island the depression turns at right angles 
 sharply to the south and extends twenty-five miles between 
 mountain ranges forming Russell Fiord. Into this fiord 
 
 Fio. 20— Map showing hjrpothetlcal former extension of glaciere during ice-flood stage, 
 based on observations of the height reached by the glaciers at a number of points. 
 (From XJ. S. Geological Survey.) 
 
 numerous local glaciers descend from both sides. The evi- 
 dence is clear that at a comparatively recent time, probably 
 as late as the visit of Vancouver near the close of the 18th 
 
32 THE ICE AGE IN NORTH AMERICA. 
 
 century, the Malaspina Glacier, and others near its south- 
 eastern border, had advanced so as to completely fill Disen- 
 chantment Bay and transform Russell Fiord into a long nar- 
 row lake, dammed up by the ice at the mouth of the bay. 
 According to Tarr,* the evidences of thi&recent advance are 
 abundant in the moraines that were pushed up on the moun- 
 tain slopes east of Yakutat Bay. But, for some time previous 
 to 1905, a recession had been in progress along the front of 
 all the separate glaciers into which the original confluent 
 glacier had been resolved by the general retreat. Thus he 
 writes: 
 
 There is a remarkable change in progress in at least 
 four of the many valley glaciers of the Yakutat Bay region — 
 the Variegated, Haenke, Atrevida, and Marvine. This change 
 is of the nature of a paroxysmal thrust, as a result of 
 which the ice is badly broken, as if a push from behind had 
 been applied with such vigor as to break the rigid resisting 
 ice mass in front. In each case the effect of this thrust is 
 felt from far up the moimtain valley well down toward the 
 terminus of the glacier, and in the Haenke and Marvine 
 glaciers to their very end. 
 
 In Variegated and Atrevida glaciers the ice has been 
 broken for a distance of five to seven miles: in Marvine 
 glacier the breaking extends fully fifteen miles. The crevassing 
 in all cases extends completely across the valley portion of 
 the glacier and down into the stagnant, or nearly stagnant, 
 moraine-covered margin. In all cases, too, the thrust is 
 accompanied by a forward movement of the margin; and in 
 at least three cases — ^the Variegated, Haenke, and Atrevida — 
 there has been a distinct thickening of the ice as a result of 
 the forward thrust. . . . Such a remarkable change 
 in the condition of the glaciers as to transform long-stag- 
 nant, unbroken, moraine-covered valley glaciers into a laby- 
 rinth of crevasses in the short interval of ten months — a 
 phenomenon, so far as known, not elsewhere recorded — calls 
 for a special explanation. 
 
 *"United States Geological Survey, Professional Paper" 64, pp. 91-106. 
 
>, 
 
GLACIERS ON THE PACIFIC COAST. 33 
 
 Professor Tarr attributes this remarkable advance to the 
 effect of the earthquake which occurred in the region in 1899, 
 six years before. This earthquake, which was sufficient to 
 elevate a portion of the coast forty-seven feet, he supposes to 
 have shaken large quantities of snow down from the more 
 elevated peaks upon the head of the glaciers, and that it 
 took all the intervening six years to make its influence felt 
 at the margin. Thus, as the weather bureau, when the extent 
 of the rainfall at the sources of a great river is known, can 
 predict when the swollen current will reach successive points 
 along the river valley, so the glacialist can foretell, from the 
 snow-fall over the nev4, when its influe'nce will be felt below 
 through the more resisting medium of the glacial ice. 
 
 The suddenness with which this advance began and the 
 vigor Avith which it went forward afford an interesting com- 
 mentary upon the prevailing notions entertained concerning 
 the "uniformity of nature's operations," and make it easier 
 for us to credit the vast changes which appear to have taken 
 place in this region since Vancouver's visit in the latter part 
 of the 18th century. 
 
 Vancouver's account of the glacial phenomena along this 
 coast is still both instructive and interesting, and in places 
 curious. 
 
 Between these points [Pigot and Pakenham] a bay is 
 formed, about a league and a half deep toward the north- 
 northwest, in which were seen several shoals and much ice ; 
 the termination of this bay is bounded by a continuation of 
 the above range of lofty mountains. On this second low pro- 
 jecting point, which Mr. Whidbey called " Point Pakenham," 
 the latitude was obsei-ved to be 60° 59^', its longitude 212° 29'. 
 The width of the arm at this station was reduced to two miles, 
 in which were several half-concealed rocks, and much floating 
 ice, through which they pursued their examination, to a point 
 at the distance of three miles along the western shore, which 
 still continued to be compact, extending north 30° east ; in 
 this direction they met such innumerable huge bodies of ice, 
 some afloat, others lying on the ground near the shore in ten 
 
GLACIERS ON THE PACIFIC COAST. 35 
 
 or twelve fathoms water, as rendered their further progress 
 up the branch rash and highly dangerous. This was, however, 
 very fortunately, an object of no moment, since before their 
 return they had obtained a distinct view of its termination, 
 about two leagues farther in the same direction, by a firm and 
 compact body of ice reaching from side to side, and greatly 
 above the level of the sea ; behind which extended the con- 
 tinuation of the same range of lofty mountains, whose summits 
 syemed to be higher than any that had yet been seen on the coast. 
 
 While at dinner in this situation they frequently heard a 
 very loud, rumbling noise, not unlike loud but ' distant thun- 
 der ; similar sounds had often been heard when the party was 
 in the neighborhood of large bodies of ice, but they had not 
 before been able to trace the cause. They now found the 
 noi.se to originate from imoiense ponderous fragments of ice, 
 breaking off from the higher parts of the main body, and fall- 
 ing from a very considerable height, which in one instance 
 produced so violent a shock that it was sensibly felt by the 
 whole party, although the ground on which they were was 
 at least two leagues from the spot where the fall of ice had 
 taken place. . . . 
 
 The base of this lofty range of mountains [between Elias' 
 and Fairweather], now gradually appi'oached the sea-side ; 
 and to the southward of Cape Fairweather it may be said 
 to be washed by the ocean ; the interruption in the sum- 
 mit of these very elevated mountains, mentioned by Captain 
 Cook, was likewise conspicuously evident to us as we sailed 
 along the coast this day, and looked like a plain composed of a 
 solid mass of ice or frozen snow, inclining gradually toward 
 the low border ; which, from the smoothness, uniformity, 
 and clean appearance of its surface, conveyed the idea of ex- 
 tensive waters having once existed beyond the then limits of 
 our view, which had passed over this depressed part of the 
 mountains, until their progress had been stopped by the 
 severity of the climate, and that, by the accumulation of suc- 
 ceeding snow, freezing on this body of ice, a barrier had become 
 formed that had prevented such waters from flowing into the 
 sea. This is not the only place where wo had noticed the like 
 appearance : since passing the icy bay mentioned on the 38th 
 
36 TEE ICE AGE IN NORTH AMERICA. 
 
 of June, other valleys had been seen strongly resembling this, 
 but none were so extensive, nor was the surface of any of them 
 so clean, most of them appearing to be very dirty. I do not, 
 however, mean to assert that these inclined planes of ice must 
 have been formed by the passing of inland waters thus into 
 the ocean, as the elevation of them, which must be many 
 hundred yards above the level of the sea, and their having 
 been doomed for ages to perpetual frost, operate much against 
 this reasoning ; but one is naturally led, on contemplating any 
 phenomenon out of the ordinary course of nature, to form 
 some conjecture, and to hazard some opinion as to its origin, 
 which on the present occasion is rather ofEered for the purpose 
 of describing its appearance, than accounting for the cause of 
 its existence.* 
 
 Westward from Mt. St. Elias the lofty semicircular ranges 
 culminating in Mount Wrangell and Mount McKinley, both 
 of which attain an elevation of 20,000 feet (the former being 
 a live volcano), aboimd with glaciers beside which those of 
 the Swiss Alps would seem insignificant. While from the 
 flanks of the Cbugatch Range immense streams of ice descend 
 to Prince William Sound, and add greatly to the gloomy gran- 
 deur of its scenery. Glaciers are also numerous in the Kenai 
 and Alaskan peninsulas as far to the westward as longitude 
 162°, and one even has been observed upon the island of 
 Unalaska. 
 
 Beyond these ranges the broad valleys of the Kuskovim 
 and the Yukon rivers are chiefly characterized by sparsely 
 covered timber areas and tundras in many respects similar to 
 the Arctic litoral of Siberia, where the soil is frozen to a 
 great' depth, the heat of the short summer being able to melt 
 scarcely more than a few inches below the surface, sections in 
 many places showing alternate layers of earth and pure ice. 
 In Alaska, however, a few glaciers again appear in the high- 
 lands of the far north. 
 
 At Eschscholtz Bay, on Kotzebue Sound, in latitude 66° 
 
 *"Voyageof Discovery around the World," vol. v, pp. 312-314, 358-360. 
 
I c o 
 
 '^■^elo/ig. y' S) .\^<"igent Pt. 
 
 "l-Sarr.u. "-P :E A. ^ 
 
 A 
 
 
 i^B"" 
 
 h-''o. 
 
 CHalket 
 
 ISanmng 
 -«~ Ft 
 
 J AIEUTIA 
 
 '3 SCALE 
 
 a^TToo ( 
 
 ■e 
 
 ^ I N 
 
 
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 ^-^-^ 
 
 iVr 
 
 
 
 >u,.^ 
 
 
 ^^■Ki 
 
 
 
 
 '■•'Vti 
 
 '% 
 
 tA 
 
 ■"niB 
 
 '"'■OA, 
 
 >^' 
 
 
 PH.YSICA 
 
 eCALl 
 
 5 60 100^ 
 
 REFE 
 
 ALTITU DES IN FEET. 
 
 BU B to BOO, Very L. 
 
 te^ 500 io 1,000, Higlier 
 
 ^^ri i,000 to SfOOO, Tlateah 
 
 ^^~^ S,000 to f 0,000, Summi\ 
 
 1 Ooer W,000, Sighed 
 
 "Warm Ourrento'-j.i; 
 Glaeiert 
 
 
 c* 
 
 
 ^s/ K«VAK 1.;/ '^ - - Jell <- "l?^ Vfry'imiKS^S 
 
 !enai .. - • 1 ^DLETONj^***^ , .. .^of ^^-Sm* FaTrilrei^/^^p^ J 
 
 C Douglas 
 
 .SUTKHOON •' / 
 
 ij ' ^l> SITKHINAK t ^ 
 
 .^. flEMIDI IS / A \J 
 
 i^ F~i a 
 
 
 ^ 
 
 -^ 
 
 ^^SH-rtj.^ 
 
 Longitude 
 
 from 
 
 Greenwich 
 
GLAOIEES ON THE PACIFIC COAST. 37 
 
 15', Kotzebue discovered in 1818 a cliff of frozen mud and 
 ice " capped by a few feet of soil bearing moss and grass." * 
 Large number of bones of the " mammoth, bison (?), rein- 
 deer, moose-deer, musk-ox, and horse, were found" at the base, 
 where they had fallen down from the cliff during the summer 
 thaws. Sir Edward Belcher and Mr. G. B. Seeman after- 
 ward visited the same spot and corroborated Kotzebue's ac- 
 count. From their report it was evident that the conditions 
 in northern Alaska are very similar to those in northern Si- 
 beria, where so many similar remains of extinct and other 
 animals have been found in the frozen soil. The section de- 
 scribed at Eschscholtz Bay seems to be simply the edge of 
 the twndra which is so largely represented in the central 
 portions of the Territory. In 1880 Mr. Dall visited the local- 
 ity and gave a fuller description than had been before given. 
 The conditions are so unique that we reproduce his account : 
 
 The ice-cliffs at this point were for a considerable distance 
 double ; that is, there was an ice-face exposed near the beach 
 with a small talus in front of it and covered with a coating of 
 soil two or three feet thick, on which luxuriant vegetation was 
 growing. All this might be thirty feet in height. On climb- 
 ing to the brow of this bank the rise from that brow proved to 
 be broken, hummocky, and full of crevices and holes ; in fact, 
 a second talus on a larger scale, ascending to the foot of a sec- 
 ond ice-face, above which was a layer of soil one to tliree feet 
 thick covered with herbage. 
 
 The brow of this second bluff we estimated at eighty feet or 
 more above the sea. Thence the land rose slowly and gradu- 
 ally to a rounded ridge, reaching the height of three or four 
 hundred feet only at a distance of several miles from the sea, 
 with its axis in a north-and-south direction, a low valley west 
 from it, tbe shallow bay at Elephant Point east from it, and 
 its northern end abutting in the cliffs on the southern shore of 
 Eschscholtz Bay. There were no mountains or other high 
 land about this ridge in any direction ; all the surface around 
 was lower than the ridge itself. 
 
 * See Prestwich's " Geology," vol. ii, p. 463 et seq. 
 
38 THE ICE AGE IN NORTH AMERICA. 
 
 About half a mile from the sea, on the highest part of the 
 ridge, perhaps two hundred and fifty feet above higb-vrater 
 mark, at a depth of a foot, we came to a solidly frozen stratum 
 consisting chiefly of bog-moss and vegetable mold, but con- 
 taining good-sized lumps of clear ice. There seemed no reason 
 to doubt that an extension of the digging would have brought 
 us to solid clear ice such as was visible at the face of the bluff 
 below ; that is to say, it appeared that the ridge itself, two 
 miles wide and two hundred and fifty feet high, was chiefly 
 composed of solid ice overlaid with clay and vegetable mold. 
 
 The ice in general had a semi-stratified appearance, as if it 
 still retained the horizontal plane in which it originally con- 
 gealed. The surface was always soiled by dirty water from the 
 earth above. This dirt was, however, merely superficial. The 
 outer inch or two of the ice seemed granular, like compacted 
 hail, and was sometimes whitish. The inside was solid and 
 transparent or slightly yellow-tinged, like peat- water, but 
 never greenish or bluish like glacier-ice. But in many places 
 the ice presented the aspect of immense cakes or fragments 
 irregularly disposed, over which it appeared as if the clay, etc., 
 had been deposited. Small pinnacles of ice ran up into the 
 clay in some places, and, above, holes were seen in the face of 
 the clay bank, where it looked as if a detached fragment of ice 
 had been melted out, leaving its mold in the clay quite perfect.* 
 
 After speaking of the frequency with which the bones of 
 the mammotli and buflfalo and other animals are found, and 
 of portions of the earth which still has in it the odor of the 
 decaying flesh, Dr. Dall adds : 
 
 Dwarf birches, alders seven or eight feet high, with stems 
 three inches in diameter and a luxuriant growth of herbage, 
 including numerous very toothsome berries, grew with the 
 roots less than a foot from perpetual solid ice. 
 
 The formation of the surrounding country shows no high 
 land or rocky hills, from which a glacier might have been 
 derived and then covered with debris from their sides. The 
 continuity of the mossy surface showed that the ice must be 
 
 * " American Journal of Science," vol. cxxi, 1881, pp. 106-109. 
 
GLACIERS OS THE PACIFIC COAST. 39 
 
 quite destitute of motion, and the circumstances appeared to 
 point to one conclusion, that there is here a ridge of solid ice 
 rising several hundred feet above the sea and higher than any 
 of the land about it and older than the mammoth and fossil 
 horse, this ice taking upon itself the functions of a regular 
 stratified rock. The formation, though visited before, has not 
 hitherto been intelligibly described from a geological stand- 
 point. Though many facts may remain to be investigated, 
 and whatever be the conclusions as to its origin and mode of 
 preservation, it certainly remains one of the most wonderful 
 and puzzling geological phenomena in existence. 
 
 The same author elsewhere writes that the continuity of 
 this deposit "is broken between Kotzebue Sound and Icy 
 Cape by rocky hills composed chiefly of carboniferous lime- 
 stones, which bear no glaciers, and do not seem to have been 
 glaciated. The absence of bowlders and erratics over all this 
 area has been noted by Franklin, Beechy, and all others who 
 have explored it." * 
 
 During the period of the Russian occupancy of Alaska 
 scarcely anything was added to our knowledge of its glaciers 
 further than what is to be found in the notes of Vancouver's 
 voyage. Even the existence of Glacier Bay, which is to 
 form tlie subject of the next chapter, was not suspected till a 
 comparatively recent time, and it is not noted on any map 
 drawn previous to 1880. Muir Glacier," which is now the 
 object of greatest interest to the host of summer tourists who 
 crowd the steamers making the round trip from Portland, 
 Oregon, through the waters of southeastern Alaska, was 
 brought to the notice of the outside world by the California 
 gentleman whose name it bears, as late as 1 879, when he and 
 Rev. Mr. Young, of the Presbyterian mission at Fort Wran- 
 gel, made a voyage of discovery around the archipelago in 
 a dug-out canoe. 
 
 * " Bulletin of the Philosophical Society of Washington," vol. vi, p. 33 ; 
 quoted in Russell, as above, p. 354. 
 
CHAPTEE III. 
 
 A MONTH WITH THE MtJIE GLACIEE. 
 
 In the summer of 1886 a party of three, consisting of 
 Rev. J. L. Patton, Mr. Prentiss Baldwin, and myseK, ar- 
 ranged to visit the Mnir Glacier, at the head of Glacier 
 Bay in Alaska, for the purpose of collecting facts concerning 
 its motion, its size, its present general condition, and its 
 probable past history and future career. The present chapter 
 will detail with some minuteness the results of our observa- 
 tion. 
 
 On the 4th of August, in company with two Indians for 
 assistants, we were landed by the excursion-steamer on the 
 east side of the inlet, directly in front of the Muir Glacier, 
 with a dug-out canoe as our only means of escape, and two 
 canvas tents as our only shelter. Here we remained a whole 
 month, or until September 2d, while the steamer made a round 
 trip to Portland, Oregon, and returned with another load of 
 freight and tourists. The region is the most desolate imagi- 
 nable. Indians rarely navigate its upper waters, and it is 
 visited only by the steamer to allow tourists to behold for a 
 few hours the wonderful spectacle of a stream of ice more 
 than a mile in width, and four hundred feet in height, mov- 
 ing onward with irresistible force to meet the equally irre- 
 sistible waters of a deep tidal inlet. Those who have here, 
 for a few hours only, witnessed the " calving " of icebergs, 
 and heard the detonations preceding and accompanying the 
 falling of the masses from the ice-front, can never forget the 
 scene. Much less can we forget it, who spent a month in 
 the majestic presence of the mighty glacier. 
 
A MONTH WITH THE MUIR O LACIER. 41 
 
 Our facilities for observations were limited by several 
 unfavorable conditions. In the first place, though we were 
 there in the dry season, fifteen of the twenty-nine days 
 were so rainy that it was impossible to stir out of our tents 
 or to see far through the mists. In the second place, 
 the tides were so strong, and the winds at times so vio- 
 lent, that it was hazardous to venture far away with our 
 canoe. In the next place, the surface of the glacier is, in 
 its central portion, so intersected by yawning crevasses that 
 it was entirely out of the question to attempt to cross 
 it. Plans for measurement, different from those made 
 familiar in Professor Tyndall's book, had therefore to be 
 devised. 
 
 On the other hand, some things were favorable to obtain- 
 ing satisfactory results. The fourteen days of fair weather 
 were extremely clear and beautiful, and there are no trees 
 upon the mountains to obstruct one's view or to hinder him 
 in rambling over them. 
 
 The specific results as to the movements of the ice, and 
 as to the formation of moraines and kames, are told a little 
 later. Here a few words will be in place concerning the 
 general aspect of the region as we saw it in August. 
 
 The mountains on each side of Muir Inlet rise immedi- 
 ately from the water from three thousand to five thousand 
 feet. These we often ascended, and thus were permitted 
 repeatedly to behold one of the most marvelous views any- 
 where to be found in the world. At that season the level 
 places around our feet upon these summits were carpeted 
 •with soft green grass, interspersed with large areas of flow- 
 ers in fuU bloom. Here were extensive, gorgeously colored 
 flower-beds, where bluebells, daisies, buttercups, violets, the 
 yellow arnica-flower, and the purple epilobium, were striv- 
 ing for mastery or for recognition. On the northern slopes 
 of slight elevations great masses of snow were preserved 
 in the very midst of these brilliant flower-gardens, and, 
 from their melting, clear little pools of water were on 
 every hand inviting us to drink. The track of the mount- 
 
42 TEE ICE AGE IN NORTH AMERICA. 
 
 airi goat, the mountain lion, and of various smaller animals, 
 and the songs of birds, witnessed to the abundance of ani- 
 mal life. 
 
 To the south the calm surface of the bay opened outward 
 into Cross Sound, twenty-five miles away. The islands dot- 
 ting the surface of the smooth water below us seemed but 
 specks, and the grand vista of snow-clad mountains, guarding 
 either side of Chatham Strait, seemed gradually to come to 
 a point on the southern horizon. Westward, toward the 
 Pacific, was the marvelous outline of the southern portion 
 of the St. Elias Alps. The lofty peaks of Crillon (15,900 
 feet high) and Fairweather (15,500 feet high), about twenty- 
 five miles away, and about the same distance apart, stood as 
 sentinels over the lesser peaks. La Perouse, Lituya, and 
 their companions, which, anywhere else, would appear to be 
 mountains of the first class, being more than ten thousand 
 feet high, and rising directlv from the water's edge. At 
 one time, when on a summit overlooking Glacier Bay, it was 
 our good fortune to see the sun go down behind this mount- 
 ain-chain. Alternate shadows and golden rays of setting 
 sunlight stretched across the water and chmbed the peak on 
 which we stood. The glistering summits of the western 
 mountains were lined with the same glowing colors, while 
 the solemn procession of glaciers on their eastern flanks was 
 gradually fading in the growing darkness, and the more dis- 
 tant mountain-tops in other directions were ceasing to reflect 
 the glow of the western horizon. 
 
 In such a setting of grandeur and beauty . we gazed upon 
 tlie full face of the great glacier itself lying at our feet. 
 Below us its diminishing outlet disappeared in the waters of 
 ths bay. Distance made the rough places plain, and lent 
 enchantment to the view. Down from the mountains in 
 every direction from the north came the frozen torrents : 
 
 Glaciers to the right of us, 
 
 Glaciers to the left of us, 
 
 Glaciers in front of us, 
 Volleyed and thundered — 
 
A MONTH WITH THE MUIB GLACIER. 43 
 
 pouring into a vast amphitheatre, and then uniting their vol- 
 ume, preparatory to their exit through the entrance into Muir 
 Inlet. These numerous local glaciers united to form nine 
 main streams whose individuality could be determined all 
 across the amphitheatre by the long lines of medial moraines 
 which swept around in majestic curves fi"om every quarter, 
 like great railroad embankments in approaching some grand 
 central depot. Such is a faint description of the scene upon 
 which we gazed. Strength and beauty were here united as 
 probably nowhere else in the world. But the shades of night 
 slowly fell upon us, even in that high latitude, and we were 
 compelled to come down closer to the thundering noises of 
 the active glaciers and seek the prosaic quarter of our tents, 
 and to go about the more detailed investigation of the mar- 
 velous phenomena before us. The results I will now pro- 
 ceed to give. 
 
 The Muir Glacier enters an inlet of the same name at the 
 head of Glacier Bay, in latitude 58° 50', longitude 136° 40', 
 west of Greenwich (see Fig. 22). This bay is a body of 
 water about thirty miles long, and from eight to twelve miles 
 wide (but narrowing to about three miles at its upper end), 
 projecting in a northwest direction from the eastern end of 
 Cross Sound. The promontory separating it from the Pacif- 
 ic Ocean is from thirty to forty miles wide, and contains 
 the lofty mountain-peaks of Crillon, Fairweather, Lituya, 
 and La Perouse, whose heights have already been indicated. 
 To the east, between Glacier Bay and Lynn Canal, is a pen- 
 insala, extending considerably south of the mouth of the 
 bay, and occupied by the White Mountains, probably having 
 no peaks exceeding ten thousand feet. 
 
 Near the mouth of Glacier Bay is a cluster of low isl- 
 ands named after Commander Beardslee, of the United 
 States Navy. There are twenty -live or thirty of these, and 
 they are composed of loose material — evidently glacial debris 
 — and are in striking contrast with most of the islands and 
 shores in southeastern Alaska. These, also, like all the other 
 land to the south, are covered with evergreen forests, though 
 
44 
 
 THE IGE AGE IW NORTH AMERICA. 
 
 Fig. 22. 
 
 the trees are of moderate size ; but the islands and shores in 
 the upper part of the bay are entirely devoid of forests. 
 Willoughby Island, near the middle of the bay, is a bare 
 rock, about two miles long and fifteen hundred feet high, 
 showing glacial furrows and polishing from the bottom to 
 the top. Several other smaller islands of similar character 
 in this part of the bay show like signs of having been re- 
 cently covered with glacial ice. 
 
 The upper end of the bay is divided into two inlets of 
 
A MONTE WITH THE MUIE GLACIER. 45 
 
 unequal lengths, the ■western one being about four miles 
 wide, and extending seven or eight miles (estimated) in the 
 direction of the main axis of the bay to the northwest. The 
 eastern, or Muir Inlet, is a little over three miles wide at its 
 mouth, and extends to the north about the same distance, 
 narrowing, at the upper end, to a little over one mile, where 
 it is interrupted by the front of the Muir Glacier. The real 
 opening between the mountains, however, is here a little over 
 two miles wide, the upper part on the eastern side being oc- 
 cupied with glacial debris covering a triangular space be- 
 tween the water and the mountain about one mile wide at 
 the ice-front and coming to a point three miles below, be- 
 yond which a perpendicular wall of rock one thousand feet 
 high rises directly from the water. The mountain on the 
 west side of Muir Inlet, between it and the other fork of the 
 bay, is 2,900 feet high. That on the east is 3,150 feet high, 
 rising to about 5,000 feet two or three miles back. The base 
 of these mountains consists of metamorphic slate, whose strata 
 are very much contorted — so much so that it is difficult to 
 ascertain their system of folds. Upon the summits of the 
 mountains on both .sides are remnants of blue crystalline 
 limestone pi*eserved in synclinal axes. In the terminal mo- 
 raine deposited in front of the glacier on its eastern side are 
 numerous bowlders of very pure white marble brought down 
 in medial moraines from mountain valleys several miles to 
 the east. Granitic bowlders are also abundant. 
 
 The width of the ice where the glacier breaks through 
 between the mountains is 10,664 feet — a little over two 
 miles. But, as before remarked, the water-front is only 
 about one mile. This front does not form a straight line, 
 but terminates in an angle projecting about a quarter of a 
 mile below the northeast and northwest comers of the inlet. 
 The depth of the water three hundred yards south of the ice- 
 front is (according to the measurement of Captain Hunter, 
 of the steamer Idaho) 516 feet near the middle of the chan- 
 nel ; but it shoals rapidly toward the eastern shore. A meas- 
 urement reported to me by Dr. Jackson, made in July, 
 
L 
 
 -=3 
 - o 
 
A MONTH WITH THE MUIR GLACIER. 47 
 
 1887, with the prow of the steamer within twenty feet of 
 the ice-front, is one hundred and six fathoms (636 feet), and 
 no bottom. Accordmg to my measurements, taken by level- 
 ing up on the shore, the height of the ice at the extremity 
 of the projecting angle in the middle of the inlet was 250 
 feet, and the front was perpendicular. Back a few hun- 
 dred feet from the projecting point, and along the front 
 nearer the shores, the perpendicular face of the ice was a lit- 
 tle over 300 feet. A little farther back, on a line even with 
 the shoulders of the mountains between which the glacier 
 emerges to meet the water, the general height is 408 . feet. 
 From here the surface of the glacier rises toward the east and 
 northeast about 100 feet to the mile. On going out in that 
 direction on the ice seven miles (as near as I could estimate), 
 I found myself, by the barometer, 1,050 feet above tlie bay. 
 The main body of the glacier occupies a vast amphithea- 
 tre, with diameters ranging from thirty to forty miles. This 
 estimate was made from various views obtained from the 
 mountain-summits near its mouth, when points whose dis- 
 tances were known in other directions were in sight. Nine 
 main streams of ice unite to form the grand trunk of the 
 glacier. These branches come from every direction north 
 of the east-and-west line across the mouth of the glacier ; 
 and no less than seventeen sub-branches can be seen coming 
 in to join the main streams from the mountains near the rim 
 of the amphitheatre, making twenty-six in all. N^umerous 
 rocky eminences also rise above the surface of the ice, like 
 islands from the sea, corresponding to what are called nuna- 
 taks in Greenland. The two of these visited, situated about 
 four miles back from the front, showed that they had been 
 recently covered with ice — their surfaces being smoothed 
 and scored, and glacial debris being deposited everywhere 
 upon them. Upon the side from which the ice approached 
 these islands (the stoss side) it rose, like breakers on the sea- 
 shore, several hundred feet higher than it was immediately 
 on the lee side. A short distance farther down on the lee 
 side, however, the ice closes up to its normal height at that 
 
48 THE lOE AGE IN NORTH AMERICA. 
 
 point. In both instances, also, the lee side of these islands 
 seemed to be the beginning of important subglacial streams 
 of water — brooks running into them as into a funnel, and 
 causing a backward movement of ice and moraine material, 
 as where there is an eddy in water. In both these cases, 
 however, the lee sides of these islands were those having 
 greatest exposure to the sunshine. The surface of the ice 
 immediately in front was depressed from one to two hun- 
 dred feet below the general surface on the lee side. 
 
 The ice in the eastern half of the amphitheatre is mov- 
 ing much more slowly than that in the western half. Of 
 this there are several indirect indications : First, the eastern 
 surface is much smoother than the western. There is no 
 difficulty in traversing the glacier for many miles to the east 
 and northeast. Here and there the surface is interrupted by 
 superficial streams of water occupying narrow, shallow chan- 
 nels, running for a short distance and then plunging down 
 into fissures, or, in technical language, mmdifis, to swell the 
 larger current, which may be heard rushing along in its im- 
 petuous course far down beneath and out of sight. The 
 ordinary light-colored bands in the ice parallel with its line 
 of motion are everywhere conspicuous, and can be followed 
 on the surface for long distances. When interrupted by cre- 
 vasses they are seen to penetrate the ice for a depth of many 
 feet, and sometimes to continue on the other side of a cre- 
 vasse in a diiferent line, as if having suffered a lateral fault. 
 The color of the ice below the surface is an intense blue, and 
 over the eastern portion this color characterized the most 
 of the surface. Numerous holes in the ice, penetrating 
 downward from an inch or two to several feet and filled with 
 water, were encountered all over the eastern portion. Some- 
 times there was a stone or a little dirt in the bottom of these, 
 but frequently there was apparently nothing whatever in 
 them but the purest of water. In the shallower inclosures 
 on the surface, containing water and a little dirt, worms, 
 about as large around as a small knitting-needle and an inch 
 long, were abundant. 
 
A MOy^TS WITH THE MUIR GLACIER. 49 
 
 The character and course of the moraines on the eastern 
 half of the glacier also attest its slower motion. There are 
 seven medial moraines east of the north-and-south line, four 
 of which come in to the main stream from the mountains to 
 the southeast (see Fig. 24). Near the rim of the glacial'am- 
 phitheatre these are long distances, in some eases miles, 
 apart ; but, as they approach the mouth of the amphitheatre, 
 they are crowded closer and closer together near its eastern 
 edge, imtil in the throat itself they are indistinguishably 
 mingled. The three more southern moraines unite some dis- 
 tance above the mouth. One of these contains a large 
 amount of pure marble. This moraine gradually approaches 
 the others on either side until the distance between them 
 disappears, and its marble unites with the other material to 
 form one common medial moraine. The fifth moraine from 
 the south is about 150 yards in width, five miles back from 
 the mouth. It is then certainly as much as five and prob- 
 ably eight miles from the mountains from which the debris 
 forming it is derived. All these moraines contain many 
 large blocks of stone, some of which stand above the general 
 mass on pedestals of ice, with a tendency always to fall over 
 in the direction of the sun. One such block was twenty feet 
 square and about the same height, standing on a pedestal of 
 ice three or four feet high. It is the combination of these 
 moraines, after they have been crowded together near the 
 mouth, which forms the deposit now going on at the north- 
 east angle of the inlet just in front of the ice. Of this more 
 will be said in connection with the question of the recedence 
 of the glacier. Similar phenomena, though on a smaller 
 scale, appear near the southwest angle of the amphitheatre. 
 
 The dominant streams of ice in the glacier come from 
 the north and the northwest. These unite in the lower por- 
 tion to form a main current, about one mile in width, which 
 is moving toward the head of the inlet with great relative 
 rapidity. Were not the water in the inlet deep enough to 
 float the surplus ice away, there is no knowing how much 
 farther' down the valley the glacier would extend. The 
 
50 THE ICE AGE IN NORTH AMERICA. 
 
 streams of ice from the east and southwest have ah-eady 
 spent the most of their force on reaching the head of the 
 inlet ; and, were it not for this central ice-stream, a natural 
 equilibrium of forces would be established here independent 
 of the water, and no icebergs would be formed. The sur- 
 face of this central current of motion is extremely rough, so 
 that it is entirely out of the question to walk far out upon 
 it. On approaching this portion of the glacier from the 
 east the transverse crevasses diagonal to the line of motion 
 increase in number and size until the whole surface is broken 
 up into vast parallelograms, prisms, and towers of ice, sep- 
 arated by yawning and impassable chasms scores and hun- 
 dreds of feet in depth. Over this part of the ice the mo- 
 raines are interrupted and drawn out into thinner lines, often 
 appealing merely as patches of debris on separate masses' of 
 ice. This portion of the ice-current presents a lighter 
 colored appearance than other portions, and the roughened 
 lines of motion can be followed, as far as the eye can reach, 
 through distant openings in the mountains to the north and 
 the northwest. 
 
 The comparative rapidity of the motion in this part of 
 the ice is also manifest where it breaks off into the water at 
 the head of the inlet. As already said, the perpendicular 
 front of ice at the water's edge is from 250 to 300 feet in 
 height. From this front there is a constant succession of 
 falls of ice into the water, accompanied by loud reports. 
 Scarcely ten minutes, either day or night, passed during the 
 whole month without our being startled by such reports, and 
 frequently they were like thunder -claps or the booming of 
 cannon at the bombardment of a besieged city, and this, 
 though om- camp was two and a half miles below the ice- 
 front. Sometimes this sound accompanied the actual fall of 
 masses of ice from the front, while at other times it was 
 merely from the formation of new crevasses or the enlarge- 
 ment of old ones. Eepeatedly I have seen vast columns of 
 ice, extending up to the full height of the front, topple over 
 and fall into the water. How far these columns extended 
 
A MOyXH WJTR THE MUIR GLACIER. 51 
 
 below the water could not be told accurately, but I have 
 seen bergs floating away which were certainly 500 feet in 
 length. At other times masses would fall from near the 
 summit breaking off part way down, and splashing the spray 
 up to the very top of tlie ice, at least 250 feet. The total 
 amount of ice thus falling off is enormous. Bergs several 
 hundred feet long and nearly as broad, with a height of from 
 twenty to sixty feet, were numerous and constantly floating 
 out from the inlet. The steamer meets such bergs a hun- 
 dred miles away. The smaller pieces of ice often so cover 
 the water of the inlet two or three miles below the glacier 
 that it is with great difiiculty that a canoe can be pushed 
 through them. One of the bergs measured, was sixty feet 
 above water and about four hundred feet square. The por- 
 tion above water was somewhat irregular, so that probably a 
 symmetrical form thirty feet in height would have contained 
 it. But even at this rate of calculation the total depth 
 would be two hundred and forty feet. The cubical contents 
 of the berg would then be almost 40,000,000 feet. Occa- 
 sionally, when the tide and wind were favorable, the inlet 
 would for a few hours be comparatively free from floating 
 ice ; at other times it would seem to be full. 
 
 The movements of the glacier in its lower portions are 
 probably facilitated by the subglacial streams issuing from 
 the front. There are four of these of considerable size. 
 Two emerge in the inlet itself, and come boiling up, one at 
 each comer of the ice-front, making a perceptible current 
 in the bay. There are also two emerging from under the 
 ice where it passes the shoulders of the mountains forming 
 the throat of the glacier. These spout up, like fountains, 
 two or three feet, and make their way through a channel in 
 the sand and gravel of the terminal moraine for about a 
 mile, and enter the inlet 250 or 300 yards south of the ice- 
 front. These streams are perhaps three feet deep and from 
 twenty to forty feet wide, and the current is very strong, 
 since they fall from 150 to 250 feet in their course of a mile. 
 It is the action of the subglacial streams neai the corners of 
 
52 THE ICE AGE IN NORTE AMERICA. 
 
 the inlet which accounts for the more rapid recession of the 
 glacier-front there than at the middle point projecting into 
 the water south of the line joining the east and west corners. 
 It was also noticeable that the falls of ice were much more 
 frequent near these corners, and the main motion of the ice 
 as afterward measured was, not toward the middle point 
 projecting into the inlet, but toward these corners where the 
 subglacial streams emerged below the water. 
 
 Ko small difficulty was encountered in securing direct 
 measurements of the motion ; and, as the results may be 
 questioned, I will give the data somewhat fully. As it 
 was impossible to cross the main current of the glacier, we 
 were compelled to take our measurement by triangulation. 
 But even then it seemed at first necessary to plant flags as 
 far out on the ice as it was safe to venture. This was done 
 on the second day of our stay, and a base-line was established 
 on the eastern shore, about a mile above the mouth, and the 
 necessary angles were taken. But, on returning to repeat the 
 observations three or four days afterward, it was found that 
 the ice was melting from the surface so fast that the stakes 
 had fallen, and there were no means at command to make 
 them secure. Besides, they were not far enougli out to be 
 of much service. It appeared also that the base-line was 
 on a lateral moraine, which was, very likely, itself in motion. 
 But by this time it had become evident that the masses of 
 ice uniting to compose the main stream of motion retained 
 their features so perfectly from day to day that tbere was no 
 difficulty in recognizing many of them much farther out 
 than it was possible to plant stakes. Accordingly, another 
 base-line was established on the east side opposite the pro- 
 jecting angle of ice in the inlet. From this position eight 
 recognizable points in different portions of the ice-field were 
 triangulated — the angles being taken with a sextant. Some of 
 the points were triangulated on five different times, at inter- 
 vals from the 11th of August to the 2d of September. Others 
 were chosen later and triangulated a less number of times. 
 
 The base-line finally chosen (marked B on Fig. 24) was at 
 
A MONTH WITE THE MUIR GLACIER. 
 
 53 
 
 the foot of the mountain exactly east by the compass from 
 the projecting angle of ice in the inlet. The elevation of 
 the base-line was 408 feet above tide— corresponding to that 
 of the lee-front. The distance of this projecting point of 
 ice (marked C on Fig. 24) from the base-line was 8,534 feet, 
 and it remained very nearly stationary during the whole 
 time — showing that the material breaking off from the ice- 
 
 
 Fig. 24.— Map of Muir Inlet, showing converging moraines, and form of front Buried 
 forest. A ; base of triangalation, B. 
 
54 THE ICE AGE IN NORTH AMERICA. 
 
 front was equal to that pushed along by the forward move- 
 ment. Satisfactory observations were made upon eight other 
 points numbered and located on Fig. 24. 
 
 No. 1 was a pinnacle of ice 1,476 feet north by 30° east 
 from 0. The movement from August 14th to August 24th 
 was 1,653 feet east by 15° south. After this date the pinna- 
 cle was no longer visible, having disappeared along the wast- 
 ing line of front between C and the subglacial stream at the 
 northeast corner of the inlet. This was so near the front as 
 to be left out of the ordinary calculations. 
 
 No. 2 was a conspicious pinnacle of ice 2,416 feet north 
 by 16° east of C. Observations were continued upon this 
 from August 11th to September 2d. The total distance 
 moved during that time was 1,417 feet, or about sixty-five 
 feet per day. From August 14th to August 24th the move- 
 ment was 715 feet, or about seventy-one feet per day. The 
 difference is, however, perhaps due to the neglect to record 
 the hours of the day when the observations were taken. As 
 these observations were wholly independent of each other, 
 their substantial concordance demonstrates that there was no 
 serious error in the observations themselves. The direction 
 of movement of this point of ice was very nearly the same 
 as that of the preceding, namely, east 16° south. This also 
 is toward the subglacial stream emerging from the northeast 
 corner of ^the inlet. 
 
 No. 3 was observed only from August 20th to August 
 24th. It was situated 3,893 feet north by 62° east of C, and 
 moved 105 feet in a westerly direction, about twenty-six feet 
 per day. The westerly course of this movement probably 
 arose from its being near where the easterly and northeast- 
 erly currents joined the main movement. 
 
 No. 4 was 5,115 feet north, 42° east of C, and moved 
 from August 20th to August 24th 143 feet in a southeast- 
 erly direction, or thirty-six feet per day. 
 
 No. 5 was 5,580 feet north, 48° east of C, and moved 289 
 feet from August 20th to August 24th in a direction east by 
 39° south, or seventy-two feet per day. 
 
A MONTH WITH THE MUIR GLACIER. 55 
 
 No. 6 was 5,473 feet north, 70° east of C, and moved 232 
 feet from August 11th to September 2d in a direction sonth 
 66° east, or ten feet per day. 
 
 No. 7 was 6.903 feet north, 59° east of 0, and moved 89 
 feet between August 14th and' August 24th, in a direction 
 south 3° east, about nine feet per day. 
 
 No. 8 was 7,507 feet north, 62° east of C, and moved 265 
 feet from August 14th to August 24th, in direction south 56° 
 east. These last three points lay in one of the moraines on 
 the east side of the line of greatest motion and parallel with 
 •it. These moraines are much interrupted in their course by 
 gaps. 
 
 It is observable that these points are all east of the center 
 of the main line of most rapid motion, and are tending with 
 varying velocity toward the northeast comer of the inlet, 
 where the powerful subglacial stream emerges from below 
 the water-level. Doubtless, on the other side of the center 
 of motion, and at the same relative distance from the front, 
 the ice would be found tending toward the northwest corner 
 of the inlet, where a similar subglacial stream emerges. 
 
 From these observations it would seem to follow that a 
 stream of ice presenting a cross-section of about 5,000,000 
 square feet (5,000 feet wide by about 1,000 feet deep) is 
 entering the inlet at an average rate of forty feet per day 
 (seventy feet in the center and ten feet near the margin of 
 movement), making about 200,000,000 of cubic feet per day 
 during the month of August. The preceding remarks upon 
 the many indirect evidences of rapid motion render the cal- 
 culation perfectly credible. What the rate may be at other 
 times of the year there are at present no means of knowing. 
 
 The indications that the glacier is receding, and that its 
 volume is diminishing, are indubitable and numerous. The 
 islands of southern Alaska are ordinarily covered with forests 
 of cedar, hemlock, and fir, up to the level of 1,500 or 2,000 
 feet above tide. But to this rule the shores and islands of 
 the upper part of Glacier Bay are a striking exception. Near 
 the mouth of the bay, forests continue to occur as in other 
 

 
 J2 ==> 
 
 So 
 
 iti "- V) 
 
A MONTH WITH THE MUIR OLAGIER. 57 
 
 parts, only on a diminished scale ; but in the upper half of 
 the bay all the shores and islands are perfectly bare of forests, 
 and the rocks retain in the most exposed situations fresh 
 grooves and strisB of glacial origin. It would be impossible 
 for rocks so exposed in such a climate to retain these for an 
 indefinite length of time. Far up on the mountains, also, 
 there are remnants of glacial debris in situations such that 
 the material could not have resisted erosive agencies for any 
 great length of time. The trifcngular-shaped terminal moraine 
 on the eastern side, just below the ice-front, presents some 
 interesting features bearing on the same point. This extends 
 three miles below the glacier, and in its lower portions is 
 thinly covered with vegetation. This covering becomes less 
 and less abundant as the glacier is approached, until, over the 
 last mile, scarcely any plants at all can be found. Apparently 
 this is because there has not been time for vegetation to 
 spread over the upper portion of the moraine since the ice 
 withdrew, for on the mountains close by, where the exposure 
 has been longer, there is a complete mr.tting of grass, flower- 
 ing plants, and shrubs. Again, in this triangular moraine- 
 covered space there are five distinct transverse ridges, mark- 
 ing as many stages in the recession of the ice-front (see Fig. 
 24). These moraines of retrocession run parallel with the 
 ice-front on that side, and at about equal distances from each 
 other, each one rising from the water's edge to the foot of the 
 mountain, where they are 408 feet above tide. An inspec- 
 tion of the upper moraine-ridge shows the manner of its for- 
 mation. This transverse ridge is half a mile below the ice- 
 front, and is still underlaid in some portions with masses of 
 ice ninety feet or more in thickness, which are melting away 
 on their sides and allowing the debris covering them to shde 
 down about their bases. Kettle-holes are in all stages of for- 
 mation along this ridge. The subglacial stream emerging 
 from the southeast comer of the glacier next the mountain 
 rushes along just in the rear of this moraine-ridge, and in 
 front of a similar deposit in process of formation on the very 
 edge of the ice where the medial moraines spoken of termi- 
 
58 THE ICE AOE IX NORTH AMERICA. 
 
 nate. Eventually tliis stream will break out in tlie rear of 
 that deposit also, and leave another ridge similar to the one 
 
 Fig. 26.— In the foreground on the ri^ht ie a mass of ice, one half mile in front of the gla- 
 cier, one hundred or more feet thick, covered with gravel, slowly sliding down to form 
 the rim of a kettle-hole. The mountain back is 3,100 feet high. Near B, Pig. 22. 
 
 now slowly settling down into position south of it. This first 
 ridge south of the subglacial stream, with its ice still melting 
 in exposed positions under its covering of gravel, can not be 
 many years old. 
 
 Still another sign of the recent date of this whole moraine 
 appears at various places where water-courses, coming down 
 from the mountain, are depositing superficial deltas of debris 
 upon the edge of the glacial deposit. These deltas are very 
 limited in extent, though the annual deposition is by no 
 means insignificant. At the southern apex of the moraine, 
 three miles below the ice-front, and but one hundred or two 
 hundred yards from our camp, great ipiautities of dehris came 
 tearing down in repeated avalanches during a prolonged sea- 
 son of rain. Twenty-five years would be more than ample 
 for the formation of the cone of debris at the foot of this line 
 of avalanches. Thus there can be no reasonable doubt that 
 
A MONTH WITH THE MUIR OLAOIER. 59 
 
 during the earlier part of this century tlie ice filled the inlet 
 several miles farther down than now. And there can be 
 scarcely less doubt that recently the glacier filled the inlet, 
 2,500 feet above its present level near the front ; for the 
 glacial debris and strise are very marked and fresh on both 
 mountains flanking the upper part of the inlet up to that 
 height, and the evidences of an ice-movement in the direction 
 of the axis of the bay are not wanting as high as 3,700 feet 
 on the eastern mountain, where I found fresh striae running 
 north by south, and directly past the summit, which rises 
 1,000 or 1,500 feet still higher, just to the east. 
 
 To this circumstantial evidence may be added what seems 
 to be an irresistible inference from the notes of Vancouver's 
 party in 179i. This party entered Cross Sound in small 
 boats, and penetrated as far as the head of Lynn Canal and 
 Juneau. 
 
 The following is the record. We should premise, how- 
 ever, that the point referred to as seven miles from Point 
 Dundas is probably that at the southeastern comer of Gla- 
 cier Bay, and the " spacious inlet lying in an east-southeast " 
 direction is probably the channel extending toward Chatham 
 Strait. But certainly, no one looking from that point at the 
 present time would speak, as this report does, of this inlet as 
 seeming to be " entirely occupied by one compact sheet of 
 ice as far back as the eye could distinguish." Nor would 
 the observer at the present time say that, to the north and 
 east, the two large open bays formed by the shores of the 
 continent seemed to be " terminated by compact solid mount- 
 ains of ice rising perpendicular from the water's edge." 
 The ice is now full twenty-five miles away from that point, 
 and the ice-front is not sufficiently prominent to make such 
 an impression as this. It is hence more than probable that, 
 at that time, the ice extended down nearly to the mouth of 
 the bay. 
 
 The morning of the 13th [July], though unpleasant, was 
 rather more favorable to their pursuit, which was still greatly 
 
 7 
 
60 TEE ICE AGE IN NORTH AMERICA. 
 
 impeded by the ice. From the east point of this branch, 
 which I have called Point Dundas, situated in latitude 58° 21', 
 longitude 334° 1', the coast takes an irregular east-northeast 
 direction about seven miles to a point whence this branch of 
 the [Cross] Sound appeared to be very extensive in an east- 
 southeast point of view, and was upward of three leagues across. 
 The party proceeded from Point Dundas to this station, 
 through a channel from two to three miles in width, between 
 the continental shore and an island about seven miles long 
 and three miles broad, lying in a northeast and southwest di- 
 rection. This spacious inlet presented to our party an ardu- 
 ous task, as the space between the shores on the northern and 
 southern sides seemed to be entirely occupied by one compact 
 sheet of ice as far as the eye could distinguish. ... To 
 the north and east of this point the shores of the continent 
 form two large open bays, which were terminated by compact 
 solid mountains of ice, rising perpendicularly from the water's 
 edge, and bounded to the north by a continuation of the united 
 lofty frozen mountains that extend eastward from Mount Fair- 
 weather. In these bays also were great quantities of broken 
 ice, which, having been put in motion by the springing up of 
 a northerly wind, was drifted to the southward, and, forcing 
 the boats from the northern shore, obliged them to take shel- 
 ter round the northeast point of the above island. This made 
 Mr. Whidbey apprehensive that the still apparent connected 
 body of ice, from side to side, would at length oblige him to 
 abandon his researches by this route, unless he should find it 
 possible to force a passage through this formidable obstruc- 
 tion. 
 
 In attempting this, the party succeeded far beyond their 
 expectations, for they gained an open navigation, and by four 
 in the afternoon arrived at a low and nearly round island 
 about two leagues in circuit, lying from the former island 
 north 83° east, distant three leagues. This island is moder- 
 ately elevated, its shores pleasant and easy of access, and well 
 stocked with timber, mostly of the pine tribe. It presented a 
 much more inviting appearance than they had been accustomed 
 to behold, and the weather being more favorable than for 
 some time jjast, they continued along the continental shore. 
 
A MONTH WITH THE MUIE OLACIER. 61 
 
 passing within some islets that lie about a league to the east- 
 ward of the round island, until nine in the evening, when it 
 became calm, and the party rested for the night at the entrance 
 of a brook, in a bay on the northern or continental shore, 
 which from the round island lies south 83° east, distant ten 
 miles.* 
 
 If we understand this, the bay to the north is Glacier 
 Bay, down which the ice must then have extended south of 
 Willoughby Island and to within a few miles of Cross Sound. 
 Otherwise no such description could have been given. The 
 bay to the east is probably the extension of the sound toward 
 the mouth of Lynn Canal, and very likely glaciers at that time 
 came down toward the west from the White Mountains and 
 produced the appearance described. From what has already 
 been said of the evidence showiag the present recession of 
 the Muir Glacier, it is not at all incredible that glaciers 
 nearly filled the whole bay a hundred years ago. 
 
 All this is necessary to a comprehension of a most inter- 
 esting problem presented by the buried forests near the south- 
 west corner of the glacier (see A, Fig. 24). Below this comer, 
 and extending for about a mile and a half, there is a gravel 
 deposit, similar to that on the eastern side, except that it is 
 not marked by transverse ridges, but is level-topped, rising 
 gradually from about 100 feet at its southern termination tO' 
 a little over 300 feet where it extends north and west of the 
 ice-front (see Fig. 24). The subglacial stream entering the 
 inlet just below the southwest comer of the ice emerges from 
 the ice about a mile farther up, on the north side of the pro- 
 jecting shoulder of the western mountain which forms that 
 side of the gateway through which the glacier enters the in- 
 let. This stream comes principally from the decaying western 
 branch of the glacier before alluded to, and, after winding 
 around the projecting shoulder of the mountain, which is 
 315 feet above tide, has worn a channel through the gravel 
 
 * " Voyage of Discovery around the World," vol. v, pp. 420^23. 
 
62 
 
 THE ICE AQE IX SOBTII AMERICA. 
 
 deposit lying between the lower mile of the glacier and the 
 mountain a short distance to the southwest. About half-way 
 down, a small brook, coming frou] between this latter mount- 
 ain and that whose shoulder foi-ms the western part of the 
 gateway just north of it, joins the main stream issuing from 
 the glacier on this side. Where these streams unite, at A, 
 they are now uncovering a forest of cedar-trees in perfect 
 preservation, standing upright in the soil in which they 
 
 Fig. 27— Burled Forest on the Mulr Glacier, looking west. 
 
 grew, with the Jnimus still about their roots. An abundance 
 of their cones, still preserving their shape, lies about their 
 roots ; and the texture of the wood is still unimpaired. One 
 of these upright trunks measured ten feet in circumference 
 about fifteen feet above the roots. Some of the smaller up- 
 right trees have tlieir l)ranches and twigs still intact, pre- 
 serving the normal conical appearance of a recently dead 
 cedar-tree. 
 
 These trees are in various stages of exposure. Some of 
 
A MOXTH WITH THE MUIR LACIER. 
 
 63 
 
 them ai-e uncovered to the roots ; some are washed wholly out 
 of the soil ; while others are still buried and standing npright, 
 in horizontal layers of fine sand and gravel, some with tops 
 projecting from a depth of twenty or thirty feet, others being 
 doubtless entirely covered. The roots of these trees are in a 
 compact, stiff clay stratum, bine in color, without grit, inter- 
 sected by numerous minute rootlets, and which is, in places, 
 twenty feet thick. There is also, occasionally, in this sub- 
 
 FlG. 28.— Shows stumps of trees on east side of the glacial torrent. Note the line of sep- 
 aration ijetween the enveloping sand and the soil in which the roots are imbedded. 
 A stump appears on the right, .split in two, but one half standing. The gravel corre- 
 sponds in height with that on the west side. The glacier appears in the background 
 on the right. (From photograph, looking north.) 
 
 stratum of clay, a small fragment of wood, as well as some 
 smooth pebbles from an inch to two feet in diameter. The 
 surface of this substratum is at this point 85 feet above the 
 inlet. The deposit of sand and gravel covering the forest 
 rises 115 feet higher, and is level-topped at that lieight, but 
 rising toward the north till it reaches the shoulder of the 
 mountain at an elevation of 300 feet. The trees are essen- 
 tially like those now growing on the Alaskan mountains. 
 Manv of them have been violently broken off from five to 
 
64 TEE ICE A6E IN NORTH AMERICA. 
 
 twenty feet above their roots. This has been done by some 
 force that has battered thein from the upper side at the point 
 of fracture. Evidently cakes of ice brought down by the 
 streams indicated in the map, when flowing at various high- 
 er levels than now, have accomplished this result ; for the 
 trunks in the main stream were battered on the north side, 
 while those in the gully worn by the lateral stream were bat- 
 tered from the west side. 
 
 From this description the explanation would seem to be 
 evident. At some period, when the ice occupied only the 
 upper part of the valley to the north of this point, forests 
 grew over all the space lying southwest of the present ice- 
 'front. As the ice advanced to near its present position, the 
 streams carrying oflE the surplus water from the western half 
 of the advancing glacier were suddenly turned into the pro- 
 tected space occupied by this forest, where they deposited 
 their loads of sand and gravel. A cause very likely com- 
 bining to facilitate deposition in this spot has not yet been 
 spoken of, but is evident from a glan'^e at the maps. A trans- 
 verse valley passes just below this point from Muir Inlet to 
 the western inlet into which Glacier Bay divides. This 
 transverse valley is at present occupied by a decaying glacier 
 opening into both inlets, and sending a subglaeial stream 
 through a long, narrow series of moraines, into Muir Inlet 
 about two miles to the south. Now, when a general advance 
 of the ice was in progress, this transverse glacier probably 
 pushed itself down into the inlet across the path of the ice 
 moving from the north, and so formed an obstruction to the 
 water running from the southwest corner of the main glacier, 
 thus favoring the rapid deposition which so evidently took 
 place. When this inclosed place was filled up, and the ad- 
 vancing ice had risen above and surmounted the projecting 
 shoulder of the mountain just to the north, that rocky barrier 
 protected a portion of the forest from the force of the ice- 
 movement, causing the ice to move some distance over the 
 top of the superincumbent gravel before exerting its full 
 downward force. Thus sealed up on the lee side of this pro- 
 
A MONTH WITH THE MUIR GLACIER. 
 
 (35 
 
 tecting ridge of rock, there would seem to be iio limit to the 
 length of time the forest might be preserved. I see no rea- 
 son why this forest may not have existed before the Glacial 
 period itself. 
 
 The existence of other forests similarly preserved in tliat 
 vicinity is amply witnessed to by many facts. One upon the 
 island near the west shore, fom- miles south, is now exposed 
 in a similarly protected position. Furthermore, the moraine, 
 already described on the east side of the inlet, contains mnch 
 wood ground up into slivers and fragments. Indeed, our 
 whole dependence during the month for fuel was upon such 
 fragments lying exposed in the moraine. Occasional chunks 
 of peat or compact masses of sphagnum formed a part of the 
 debris of this moraine. These also occurred on some of the 
 
 ~n 
 
 Fig. 29— Mulr Glacier from an elevation of 1 ,800 feet. 
 
 medial moraines on the eastern side. I did not go up tliem 
 far enough to learn directly their origin ; but, as no forests 
 
66 THE 10 E AGE IN NORTH AUERIGA. 
 
 were visible anywhere in that direction, it is presumable that 
 they had been recently excavated from preglacial forests simi- 
 lar in situation to that now exposed on the west below the 
 ice-front. 
 
 The capacity of the ice to move, without disturbing them, 
 over such gravel deposits as covered the forests, is seen also 
 in the present condition of the southwestern corner of the 
 glacier itself. As the ice-front has retreated along that 
 shore, large masses of ice are still to be seen lapping over 
 upon the gravel. These are portions of the glacier still sus- 
 tained in place by the underlying gravel, while the water of 
 the inlet has carried the ice from the perpendicular bank 
 clear away. This phenomenon, and that of the general per- 
 pendiculai- front presented by the ice at the water's edge, 
 accord with the well-known fact that the surface of the ice 
 moves faster than the lower portions. Otherwise the ice- 
 columns at the front would not fall over into the water as 
 they do. 
 
 The formation of kames, and of the knobs and kettle- 
 holes characteristic both of kames and of terminal moraines, 
 is illustrated in various places about the mouth of Muir Gla- 
 cier, but especially near the southwest comer, just above the 
 shoulder of the mountain where the last lateral branch comes 
 in from the west. This branch is retreating, and has already 
 begun to separate from the main glacier at its lower side, 
 where the subglacial stream passing the buried forest emerges. 
 Here a vast amount of water-worn debris covers the ice. ex- 
 tending up the glacier in the line of motion for a long dis- 
 tance. It is evident from the situation that, when the ice- 
 stream was a little fuller than now, and the subglacial stream 
 emerged considerably farther down, a great mass of debris 
 was spread out on the ice at an elevation considerably above 
 the bottom. Now that the front is retreating, this subglacial 
 stream occupies a long tunnel, twenty-iive or thirty feet high, 
 in a stratum of ice that is overlaid to a depth, in some places, 
 of fifteen or twenty feet with water-worn glacial debris. In 
 numerous places the roof of this tunnel has broken in, and 
 
A MONTH WITH THE MUIR GLACIER. 67 
 
 the tunnel itself is now deserted for some distance by the 
 stream, so that the debris is caving down into the bed of the 
 old tunnel as the edges of ice melt away, thus forming a 
 tortuous ridge, with projecting knolls where the funnels into 
 the tunnel are oldest and largest. At the same time, the ice 
 on the sides at some distance from the tunnel, where the 
 superficial debris was thinner, has melted down much below 
 the level of that which was protected by the thicker deposit ; 
 and so the debris is sliding down the sides as well as into the 
 tunnel through the center. Thus three ridges approximately 
 parallel are simultaneously forming — one in the middle of 
 the tunnel and one on each side. When the ice has fully 
 melted away, this debris will present all the comphcatious of 
 interlacing ridges, with numerous kettle-holes and knobs 
 chai-acterizing the kames ; and these will be approximately 
 parallel with the line of glacial motion. The same condition 
 of things exists about the head of the subglacial stream on 
 the east side, also near the junction of the first branch glacier 
 on the east with the main stream, as also about the mouth of 
 the independent glacier shown on the map lower down on the 
 west side of the inlet (see Fig. 24). The formation of kettle- 
 holes in the terminal ridges has already been referred to. 
 
 Considerable earthy material is carried out from the front 
 by the bergs. Pebbles and dirt were frequently seen frozen 
 into them as they were floating away. Just how many of the 
 bergs were formed from ice that originally rested on the bot- 
 tom of the inlet I have no means of telling. That some were 
 so formed seems exceedingly probable, if for no other reasons 
 because of the great amount of debris that was sometimes 
 seen frozen into them. It is by no means certain that the 
 subglacial streams boiling up near the upper comers of the 
 inlet were beneath the lowest stratum of ice. Some small 
 streams were seen pouring out from the face of the ice half- 
 way up from the water. It seems likely that a great amount 
 of sediment is conveyed into cavities in the center of the 
 glacier through the action of these subglacial streams ; and 
 so is ready for transportation when the masses break loose. 
 
68 THE IGE AGE IN NORTH AMERICA. 
 
 My estimates concerning the amount of sediment carried 
 out by subglacial streams are as follows : The amount of sedi- 
 ment contained in each United States gallon (231 cubic inches) 
 of water collected from the subglacial streams is, as deter- 
 mined by the analysis of the late Professor H. C. Foote, of 
 Cleveland, 708*48 grains. Estimating the total area occupied 
 by the glacial amphitheatre to be 1,200 square miles, and the 
 annual precipitation the same as that at Sitka (which is not 
 far from ninety-slK inches), the total amount of water which 
 must in some form annually pass into the inlet from this area 
 is 267,632,640,000 Cubic feet. Of this amoimt I estimate 
 that 77,088,000,000 cubic feet passes out as ice, or, reducing 
 this to water, about 67,000,000,000 cubic feet of liquid water. 
 (This part of the calculation is based on the fact approximate- 
 ly ascertained that a section of ice one mile wide and 1,000 
 feet deep is moving into the inlet at a rate of 40 feet per 
 day.) Subtracting the ice from the total amount, and esti- 
 mating that evaporation would probably diminish the amount 
 one eighth, the total amount of water which must issue in 
 all the subglacial streams from this glacier is 175,000,000,000 
 cubic feet. Estimating the specific gravity of the sediment 
 (which is chiefly some compound of alumina and silica) at 
 two and a half, we have, as the total amount of sediment 
 transported thus, 33,274,804 cubic yards. This equals not far 
 from one third of an inch per year eroded from the total 
 area (1,200 square miles) occupied by the glacier. This 
 would furnish one inch of sediment per year to be spread by 
 this single glacier over the bottom of Glacier Bay. This 
 confirms the statements concerning the recent recession of 
 the glacier from the lower portion of the bay, since otherwise 
 it would now be full of sediment. 
 
 Besides the Muir Glacier several others of large size, 
 such as the Grand Pacific and Hugh Miller Glaciers, descend 
 from the flanks of Mts. Crillon and Fairweather into Reid 
 Inlet, which projects several miles to the northwest from 
 Glacier Bay. These do not differ materially in appearance 
 and behavior from the Muir Glacier. 
 
A MONTH WITH THE MUIR OLAOIER. 69 
 
 I append the record of the thermometer from August 20th 
 to August 31st, giving the mean of three readings each' day 
 taken at 8 A. m., 2 p. m., and 8 p. m. The temperature of the 
 water in the upper part of the inlet was uniformly 40° Fahr. 
 
 August 20, 49-4° Fahr. 
 August 21, 48-9° Fahr. 
 August 22, 46-1° Fahr. 
 August 23, 44-6° Fahr. 
 
 August 24, 49-8° Fahr. 
 August 25, 52-7° Fahr. 
 August 26, 51-9° Fahr. 
 August 27, 46-1° Fahr. 
 
 August 28, 50-5° Fahr. 
 August 29, 45° Fahr. 
 August 30, 54-8° Fahr. 
 August 31, 50-5° Fahr. 
 
 The following is the list of plants, as identified by Pro- 
 fessor Asa Gray, found in bloom about Muir Inlet during the 
 month of August. Where the altitude is not given, they were 
 found near the tide : 
 
 Arabis ambigua, Brong August 26, 1,600 A. T. 
 
 Arenaria peploides, L August 28. 
 
 Astragalus alpinus, L August 7. 
 
 Hedysarum boreale, Nutt August 28. 
 
 Sanguisorba Canadensis August 6. 
 
 Lutkea sibbaldioides, Brong August 27. 
 
 Saxifraga Lyalli, Engl August 26. 1,600 A. T. 
 
 Saxifraga stellaris, L August 27, 3,000 A. T. 
 
 Parnassia flmbriata, Small August 27, 3,000 A. T. 
 
 Pamassia palustris, L August 6. 
 
 Epilobium latifolium, L August 6, 1,600 A. T. 
 
 Epilobinm origanifolium Lam. (?) August 28. 
 
 Solidago multiradiata, Ait August 27. 
 
 Erigeron salsuginosus. Gray, arctic form. . August 27, 3,000 A. T. 
 
 Antennaria margaritacea, arctic form August 27. 
 
 Achillea millefolium, L., arctic variety August 27. 
 
 Arnica obtusifolia, Les August 27, 1,200 A. T. 
 
 Campanula rotundifoli.i, L., vai-. Alaskana. August 28. 
 
 Gentiana platypetala (?) August 27. 
 
 Gentiana Menziesii (?) August 27. 
 
 Mertensia maritima ' August 7. 
 
 Castilleja parviflora, Brong August 28. 
 
 Salix vestita, Pursh August 6. 
 
 Habenaria hyperborea, K. Br August 27, 2,650 A. T. 
 
 Luzula parviflora, Meyer. 
 
 Poa alpina, variety vivipara August 26, 1,500 A. T. 
 
 Poa alpina, L August 26, 1,600 A. T. 
 
 Poa laxa, Hainke August 26, 1,500 A. T. 
 
70 THE lOE AOE IN NORTH AMERICA. 
 
 Phleum alpinum, L ; August 26, 1,600 A. T. 
 
 ElymuH mollis August 6. 
 
 Hordenm, sp. (?) August 6. 
 
 Fis. 30.— Blocks of stone supported on ice-pillars, showing how they fall toward the sun. 
 See above, page 49. United States Geological Survey (Knssell). 
 
A MONTH WITH THE MUIR GLACIER. 71 
 
 SUPPLEMENT TO CHAPTER III. 
 
 For various reasons it is best to let this chapter stand as 
 it was originally written. But it is necessary to append a 
 summary of the results of subsequent observations by others, 
 especially as they have a most important bearing on several 
 questions of glacial theory. During the summers of 1890 
 and 1892 Professor Harry Fielding Reid with a corps of 
 competent assistants carefully surveyed the region and made 
 extensive additions to our knowledge, not only of this glacier, 
 but of glacial movements in general. 
 
 The main facts, as determined by Professor Eeid, do not, 
 however, differ materially from ours. Our estimate of twelve 
 hundred square miles for the area of the Muir Glacier would, by 
 his calculations, be brought down to a thousand square miles. 
 He failed, however, to detect any motion in the glacier greater 
 than about ten feet per day. But it should be noted that he 
 did not measure the central, and consequently most rapidly 
 moving portion of the ice, but limited himself to calculating 
 the motion of those portions of the ice which he could traverse, 
 and upon which he could plant flags of observation. Thus, not- 
 withstanding his utmost efEorts, in going out from both direc- 
 tions, about a quarter of a mile in width, as he informs me, re- 
 mained untraversed, and his attempts to take angles, after the 
 method pursued by us, upon the masses of ice themselves, failed 
 of success. This was probably due to the fact that his base- 
 line (near B in our map on page 53) was eight hundred feet 
 higher upon the mountain than ours, so that he did not have 
 the advantage which we had of seeing the domes and pinnacles 
 of the central and higher portion of the ice projected upon the 
 sky and the dark background of the mountains beyond. Hence 
 it does not appear that there is any occasion to question the ap- 
 proximate correctness of our figures as given on page 54. If, how- 
 ever, I were to revise the estimates of the average rate of move- 
 ment in the mass of ice, I should not place it quite so high as I 
 have done on page 55, especially since in that calculation no 
 allowance was made for the decrease of velocity toward the 
 bottom. Taking this into account, together with the com- 
 
72 THE ICE AGE IN NORTH AMERICA. 
 
 parative narrowness of the area of most rapid motion, the 
 average movement of the mass is probably not over twenty 
 feet per day, and this amount would perhaps account for 
 the number of bergs floating away with the tide, especially 
 since now we must add to them the amount supplied by the 
 recession of the front of the ice. 
 
 With reference to tne evidence of the recent recession of 
 the glacier Professor Reid agrees entirely with me. By com- 
 parison of his photographs with mine he found that in "the 
 four years from 1886 to 1890 the western end of the ice front 
 has receded 1,200 yards and the eastern end 750 yards. The 
 center also has receded about 1,000 yards, so that the average 
 recession of the ice front is a little over 1,000 yards in the 
 four years, or, say a mile in seven years .... It does not 
 seem at all incredible that the ice from the various glaciers of 
 Glacier Bay may have united to fill a large part of the bay 
 100 years ago." 
 
 But it is no longer necessary to depend on this evidence 
 alone. In 1906 Messrs. F. E. and C. W. Wright made an 
 official investigation of the region with the following startling 
 results. On comparing their map with that of Professor Reid 
 made in 1892 they write that: 
 
 Beginning with Muir Glacier and its tributaries the ice 
 front has receded a maximum distance of 33,000 feet; Dirt 
 Glacier is no longer tidal; White and Adams Glaciers are 
 supplying very little ice to the general ice field; Morse Glacier 
 terminus is about one mile from tide water .... Girdled 
 Glacier and Berg Lake have not changed materially in aspect. 
 The length of the total ice front of Muir Glacier is now over 
 40,000 feet instead of 9,000 feet in 1892. The present ice 
 front passes at its northern extremity at about the position 
 of your 1,000 foot contour on the ice of 1892. This remarkable 
 decrease in elevation is undoubtedly due not only to melting 
 down but also to breaking down of the exposed ice masses. 
 The ascent of the ice mass at this point is decidedly steep and 
 the ice fairly cascades into the water. The present height of 
 the ice fronts of all the tide water glaciers is about the same 
 
A MONTH WITH THE MUIR GLACIER. 73 
 
 as noted by you in 1892 (150-250 feet), and is a noteworthy 
 fact in connection with these glaciers. Muir Inlet is at present 
 choked by the ice pack which promises to remain congested 
 so long as its source of supply is so active. A considerable 
 portion of the present front of Muir Glacier is in very shallow 
 water and in a few years should decrease in size very materially 
 unless new avenues and inlets for tidal currents are exposed 
 by the receding ice. Dying Glacier is still creeping back and 
 wasting away. 
 
 Carroll Glacier has not changed much in aspect during the 
 last fourteen years; its terminal cliff has receded about 2,000 
 feet and at present, apparently, is continuing to do so. It 
 is discharging icebergs very slowly and Queen Inlet is nearly 
 free of ice. 
 
 Rendu Glacier has also changed but little, and its front is 
 about 2,000 feet back of its position in 1892. This inlet also 
 is not impeded by any amoimt of ice. The small glacier cas- 
 cading from the west near its terminus appears to have changed 
 still less. 
 
 In Reid Inlet the changes have been very great and things 
 are still moving at a rapid rate there. The inlet was congested 
 with the ice pack last summer (1906) and on the south side 
 near the large island the ice jam was completely frozen over 
 and moved as one mass back and forth with the tides. 
 
 Grand Pacific Glacier has receded and left the large granite 
 island surrounded by water. It has receded nearly 20,000 
 feet ; but judging from the amount of ice it is now discharging 
 and the shape of its valley it will not recede so rapidly in the 
 next few years, other conditions remaining the same. 
 
 Johns Hopkins Glacier has receded about 1 1,000 feet and is 
 still sending off icebergs at a rapid rate. The unnamed glacier 
 directly east has become detached from it and is much like 
 Reid Glacier in character and appearance. 
 
 Reid Glacier has receded perhaps 5,000 feet and still 
 preserves its original aspect as indicated on your map .... 
 
 Hugh Miller Glacier no longer reaches tide water in Reid 
 Inlet and at low tide is nearly a mile back from it. The tide 
 flats are long and with only a slight grade. In Hugh Miller 
 
74 THE ICE AGE IN NORTH AMERICA. 
 
 Inlet this glacier was exposed to tide water only in the south- 
 western bay, where its front is intercepted in its central part 
 by a large promontory of light colored granite. Eight thou- 
 sand feet is approximately its recession since 1892. Charpen- 
 tier Glacier also receded about 9,000 feet and promises to con- 
 tinue its recession rapidly, especially along its southern front, 
 as its valley is opening out and allowing a greater exposure of 
 ice front to the action of tide water. 
 
 The small stagnant glacier east of Charpentier is simply 
 melting away and will probably disappear in ten or twenty 
 years. 
 
 Favorite Glacier is still receding. Wood Glacier is no 
 longer tidal and only a small part of Geikie Glacier ice front 
 is exposed to salt water. Geikie Glacier has receded about 
 5,000 feet during the past fourteen years. 
 
 On the whole, recession has been the rule for the glaciers 
 of Glacier Bay. Those glaciers have receded most whose fronts 
 have, on recession, increased appreciably in length. In the 
 past fourteen years the combined ice front of all the glaciers 
 exposed to the tide water has increased from 17,000 feet to 
 over 40,000 feet and the amount of recession has in that time 
 alone equalled that of the previous twenty years. 
 
 To the west of Glacier Bay, Brady Glacier in Taylor Bay 
 has receded considerably. In Lituya Bay, the glacier at 
 the northwestern end of the bay has advanced about one-half 
 mile since 1894; the central and southeastern glaciers have 
 apparently remained unchanged although the latter may have 
 advanced slightly.* 
 
 *H. F. Reid: "Variation of Glaciers," xii, "Journal of Geology," 
 xvi, pp. 62, 53. 
 
{fe!^iiS^a*j 
 
 Plate V-Mu(r Glacier In) 
 
CHAPTER IV. 
 
 THE GLACIERS OF GBEENLAND. 
 
 The continental proportions of Greenland, and the ex- 
 tent to which its area is covered by glacial ice, make it by 
 far the most important accessible field for glacial observa- 
 tions. The total area of Greenland can not be less than 500,- 
 000 square miles — equal in extent to the portion of the 
 United States east of the Mississippi and north of the Ohio. 
 It is now pretty evident that the whole of this area, except 
 a narrow border about the southern end, is covered by one 
 continuous sheet of moving ice, pressing outward on every 
 side toward the open water of the surrounding seas. 
 
 For a long time it was the belief of many that a large 
 region in the interior of Greenland was free from ice, and 
 was perhaps inhabited. It was in part to solve this problem 
 that Baron Nordenskiold set out upon his expedition of 
 1883. Ascending the ice-sheet from Disco Eay, in latitude 
 69°, he proceeded eastward for eighteen days across a con- 
 tinuous ice-field. Rivers were flowing in channels upon the 
 surface lite those cut on land in horizontal strata of shale or 
 sandstone, only that the pure deep blue of the ice-walls were, 
 by comparison, infinitely more beautiful. These rivers were 
 not, however, perfectly continuous. After flowing for a dis- 
 tance in channels on the surface, they, one and all, plunged 
 with deafening roar into some yawning crevasse, to find their 
 way to the sea through subglacial channels. Numerous 
 lakes with shores of ice were also' encountered- |) 
 
 " On bending down the ear to the ice," says this explbrer, 
 " we could hear on every side a peculiar subterranean hum, 
 
Fia. 31— Map of Greenland showing narrow margin free from Ice. 
 
THE GLACIERS OF GREENLAND. 77 
 
 proceeding from rivers flowing within the ice; and occasion- 
 ally a loud single report like that of a cannon gave notice of 
 the formation of a new glacier-cleft. ... In the afternoon 
 we saw at some distance from us a well-defined pillar of mist 
 which, when we approached it, appeared to rise from a bot- 
 tomless abyss, into which a mighty glacier-river fell. The 
 vast roaring water-mass had bored for itself a vertical hole, 
 probably down to the rock, certainly more than 2,000 feet 
 beneath, on which the glacier rested." * 
 
 At the end of the eighteen days, Nordenskiold found 
 himself about 150 miles from his starting-point, and about 
 5,000 feet above the sea. Here the party rested, and sent 
 two Eskimos forward on skidor — a kind of long wooden 
 skate, with which they could move rapidly over the ice, not- 
 withstanding the numerous small circular holes which every- 
 where pitted the surface. These Eskimos were gone fifty- 
 seven hours, having slept only four hours of the period. It 
 is estimated that they made about 75 miles, and attained an 
 altitude of 6,000 feet. The ice is reported as rising in distinct 
 terraces, and as seemingly boundless beyond. If this is the 
 case 225 miles from Disco Bay, there would seem little hope 
 of finding in Greenland an interior freed from ice. So we 
 may pretty confidently speak of that continental body of 
 land as still enveloped in an ice-sheet. Up to about latitude 
 75°, however, the continent is fringed by a border of islands, 
 over which there is no continuous covering of ice. In 
 south Greenland the continuous ice-sheet is reached about 
 thirty miles back from the shore. 
 
 In 1886 Dr. Rink wrote: 
 
 We are now able to demonstrate that a movement of ice 
 from the central regions of Greenland to the coast continually 
 goes on, and must be supposed to act upon the ground over 
 which it is pushed, so as to detach and transport fragments of 
 it for such a distance. . . . The plainest idea of the ice-forma- 
 tion here in question is given by comparing it with an inunda- 
 
 * " Geological Magazine," vol. is, pp. 393, 399. 
 
78 THE ICE AGE IN NORTH AMERICA. 
 
 tion. . . . Only the marginal part shows irregularity ; toward 
 the interior the surface grows more and more level, and passes 
 into a plain very slightly rising in the same direction. It has 
 been proved that, ascending its extreme verge, where it has 
 spread like a lava-stream over the lower ground in front of it, 
 the irregularities are chiefly met with up to a height of 3,000 
 feet, but the distance from the margin in which the height is 
 reached varies much. While under 68^° north latitude, it took 
 twenty-four miles before this elevation was attained ; in 62|° 
 the same height was arrived at in half the distance. . . . 
 
 A general movement of the whole mass from the central re- 
 gions toward the sea is still continued, but it concentrates its 
 force to comparatively few points in the most extraordinary 
 degree. These points are represented by the ice-fiords, through 
 which the annual surplus ice is carried off in the shape of bergs. 
 ... In Danish Greenland are found five of the first, four of 
 the second, and eight of the third (or least productive) class, 
 besides a number of inlets which only receive insignificant 
 fragments. Direct measurements of the velocity have now 
 been applied on three first-rate and one second-rate fiords, aU 
 situated between 69° and 71° north latitude. The measure- 
 ments have been repeated during the coldest and the warmest 
 season, and connected with surveying and other investigations 
 of the inlets and their environs. It is now proved that the 
 glacier branches which produce the bergs proceed incessantly 
 at a rate of thirty to fifty feet per diem ; this movement being 
 not at all influenced by the seasons. . . . 
 
 In the ice-fiord of JakobshaVn, which spreads its enormous 
 bergs over Disco Bay, and probably far into the Atlantic, the 
 productive part of the glacier is 4,500 metres (about 2^ miles) 
 broad. The movement along its middle line, which is quicker 
 than on the sides nearer the shores, can be rated at fifty feet 
 per diem. The bulk of ice here annually forced into the sea 
 would, if taken on the shore, make a mountain two miles long, 
 two miles broad, and 1,000 feet high. The ice-fiord of Tor- 
 sukatak receives four or five branches of the glacjer ; the most 
 productive of them is about 9,000 metres (five miles) broad, 
 and moves between sixteen and thirty-two feet per diem. The 
 large Karajak Glacier, about 7,000 metres (four miles) broad. 
 
TEE GLACIERS OF GREENLAND. 79 
 
 proceeds at a rate of from twenty -two to thirty-eight fefet 
 per diem. Finally, a glacier hranch dipping into the fiord of 
 Jtivdliarsuk, 5,800 metres (three miles) broad, moved between 
 twenty -four and forty-six feet per diem.* 
 
 Describing the " Isblink," in latitude 62^° north, Eink 
 
 The whole surveyed area of the inland ice in this place is 
 calculated at 450 square miles, and forms, by means of the 
 tongued shape of its foremost part, in some measure a separate 
 district, in which the principal changes of the whole margin, 
 excepting the ice-fiords, are represented. Toward the interior 
 it is bordered by a row of nunataks,\ distant about forty miles 
 from the seaward edge which our travelers had ascended as 
 their starting-point. Here the origin of the ice over which 
 they had passed was at once plainly visible ; namely, that it 
 could not have been formed on the spot, but was brought 
 thither from the interior of the continent. The nunataks 
 had been an obstacle to this movement ; on the east side, fac- 
 ing the interior, the ice was broken and piled up several hun- 
 dred feet against the rock, like breakers of an ocean, while to 
 the south and north, and between the nunataks, it poured 
 down like frozen waterfalls to be embodied in and leveled with 
 the crust over which our explorers had traveled. . . . 
 
 The recent explorations, as already mentioned, have proved 
 that what now we designate as coast-land free from ice was for- 
 merly covered with ice like the interior. This ancient ice-cov- 
 ering reached, in the immediate vicinity of the present inland 
 ice, a height of 3,000 to 4,000 feet, and, farther seaward, 2,000 
 to 3,000 feet above the sea. All the usual traces of ancient 
 ice-action, the erratic blocks and the ground rocks, are the 
 same here as in northern Europe. 
 
 * See " Transactions of the Edinburgh Geological Society " for February 18, 
 1886, vol. V, part ii, pp. 286-293. 
 
 f Nwnataks are simpjy mountain-topa projecting above the surface of the 
 ice-fields, such as were described in the account of the Muir Glacier in Alaska. 
 Nordenskiold was the first to describe them in Greenland, and gave them this 
 
80 THE lOE AGE IN NORTH AMERICA. 
 
 Eink supposes the opening of new channels for the outlet 
 of the ice through the fiords naay have so relieved the interior 
 as to account for this recedence of the ice.* 
 
 Among the most important observations upon the rate of 
 movement in the glaciers in Greenland are those made by 
 the Norwegian geologist Helland, in the summer of 1875. 
 During that season he made a series of measurements on the 
 glacier that enters the great Jakobshavn Fiord in the north- 
 ern part of Disco Bay, about latitude 70°. The width of 
 this glacier near its mouth he found to be about two miles 
 and a half. The view from the peaks in the vicinity toward 
 the east extended to a continuous ice-field on the distant 
 horizon. The rate of motion reported by Helland was so 
 great, that scientific men hesitated for some time to credit it. 
 According to his measurements, the Jakobshavn Glacier, in 
 the central portion of its current, was moving more than 
 sixty feet per day, as compared vnth the three feet per day 
 reported for Alpine glaciers. But the subsequent measure- 
 ments of Steenstrup, given above, and those of my own upon 
 the Muir Glacier in Alaska (made in 1886), amply sustain 
 the conclusions of Helland. 
 
 It is proper to observe here, again, that the movement of 
 glacial ice is affected much less by the slope of its bottom 
 than by the size of the stream itself. The friction of the 
 ice upon the bottom and sides of its channel is so great, that, 
 where the stream is both shallow and narrow, the motion 
 must be almost completely retarded. On doubling the size 
 
 * The list of explorers Riven by Rink is worthy of being honored, and is as 
 follows : " Geologist K. J. V. Steenstrup (eight summers and two winters) ; 
 Lieutenant G. Holm, of the Royal Navy (five summers and one winter) ; Lieu- 
 tenant R. Hammer, of the Royal Navy (three summers and one winter) ; Lieuten- 
 ant A. D. Jensen, of the Royal Navy (three summers) ; geologist Sylow (two 
 summers) ; painter Groth (two summers) ; supernumerary officer Larsen (one 
 summer) ; Lieutenant Garde, of the Royal Navy (two summers and one winter) ; 
 geologist Knutsen, Norwegian (two summers and one winter) ; geologist Peter- 
 sen (one summer) ; botanist Eberlin (two summers and one winter) ; painter 
 Rus Carstersen (one summer). Steenstrup and Hammer did most on the 
 fiords." 
 
THE GLACIERS OP GREENLAND. 
 
 81 
 
 of a semi-fluid stream, tlie relative amount of friction be- 
 comes very much less, so that it will move more than twice 
 
 Fig. 32,— Map of Frederikphaab rilacier, between 65" and 63°. showing course of Lienten- 
 ant Jensen in 1878 (forty-seven and a half miles). The black part, ice ; white, 
 land ; .shaded, water ; J. N., Jensen's nnnataks : D. N., Dola^er's nnnataks : white 
 lines on the black, crevasses ; arrows, frlacier-flow. Five species of plants were found 
 on the nnnataks which still survive on the White Mountains (N, H.). Dana, 
 
 as fast as before. This property of a semi-fluid is made suf- 
 ficiently evident from a homely illustration. Molasses in 
 cold weather will scarcely run at all through a gimlet-hole, 
 while it will run with considerable freedom through an 
 auger-hole. IS^ow, the glaciers of the Alps, which were the 
 subjects of Professor Tyndall's measurements, were, in com- 
 parison to those in Greenland and Alaska, about in the pro- 
 portion of a small gimlet-hole to a large auger-hole, and the 
 faster motion is really not surprising. 
 
82 THE IGE AGE IN NORTH AMEBIC A. 
 
 Helland's observations as to the amount of ice floatiBg 
 away from the glacier in bergs amply coniirm the direct cal- 
 culation. The depth of the Jakobshavn Fiord is about 
 1,200 feet, so that icebergs cf vast size can float off upon its 
 waters. The daily discharge of ice through this fiord was 
 estimated by him to be 432,000,000 cubic feet — about three 
 times the calculation I have made for the Muir Glacier in 
 Alaska. In addition to the formation of large icebergs, the 
 discharge of ice from such a glacier as that at Jakobshavn is 
 doubtless accompanied by a continual cannonade of countless 
 smaller fragments, keeping the heavens full of thundering 
 sounds and the waters fuU of commotion. From this it fol- 
 lows that the movement of the great glaciers must be rapid, 
 to account for the enormous numbers of first-class icebergs 
 wliich are encountered in the vicinity, and for the numerous 
 and immense ice-floes composed of smaller fragments. 
 
 While the attention is flxed on the movement of the gla- 
 ciers, we should not fail to note the uniform presence of 
 subglaeial streams of water emerging from their fronts. 
 Such streams are usually in proportion to the size of the gla- 
 cier, and, as already remarked, are most powerful agencies in 
 the transportation of earthy material. The amount of sedi- 
 ment thus brought out by a single subglaeial stream on the 
 west coast of Greenland is estimated to be from 15,000 to 
 20,000 tons daily ; and the amount of water discharged in 
 the stream is far larger than that which passes off as ice. 
 
 The existence of such subglaeial streams reveals much 
 concerning the condition of the glaciers themselves. The 
 question at once arises, Whence does the water come ? The 
 answer is found in the facts already mentioned by Norden- 
 skiold concerning the superficial streams of water uniformly 
 encountered on penetrating the glaciated interior of Green- 
 land. Doubtless, also, much water arises from the melting 
 of the lower strata of ice through the heat produced by the 
 friction attendant upon the motion. 
 
 Mr. Whymper's descriptions add vividness to our knowl- 
 edge of the Greenland Glacier in the latitude of Disco : 
 
THE GLACIERS OF GREENLAND. 
 
 83 
 
 In a paper coiiimunicatecl to the "Alpine Journal" in 
 1870, I wrote in relation to this part of Greenland and the 
 countrj' to its north and south: 
 
 The great ice-covered interior plateau of Greenland can 
 be seen a long way off if the weather is clear. Its summit is 
 
 Fig. 33. — Ikamiut Fjord, Grcenlaml, showing liiirif^iiig 
 the Fjord come to enter's edge. 
 
 ?lacler-> 
 
 Gliu-ier.s a I. lirad of 
 
 almost a dead level from north to south. But when one 
 comes nearer to the coast it is concealed by the hills which 
 are on its outskirts. The whole of the (outer) land on the 
 (west) Greenland coast is mountainous, and although the hills 
 scarcely ever, if ever, exceed a height of 8000 or 9000 feet, 
 they effectually conceal the inner or glacier-covered land. 
 This latter is at a distance from the coast varying from ten 
 to sixty, or more miles, and, when it is reached, there is 
 an end to land — all is ice, as far as the eye can see. Great 
 as the mass of ice is which still envelops Greenland, there 
 were times when the land was even more completely cov- 
 ered up by it; indeed, there is good reason to suppose that 
 there was a time when every atom of the country was co^'ered, 
 and that life was hardly possible for man. . . . With the 
 exception of places where the rocks are easy of disintegra- 
 
84 THE ICE AGE IN NORTH AMERICA. 
 
 tion, and the traces of glacier actioD have been to a great ex- 
 tent destroyed, the whole country bears the marks of the grind- 
 ing and polishing of ice ; and, judging by the flatnesS of the 
 curTes of the roches moutonnees, and by the perfection of the 
 polish which still remains upon the rocks, after they have sus- 
 tained many centuries of extreme variations of temperature, 
 the Glacial- period during which such efEects were produced 
 must have vastly exceeded in duration, or severity, the Glacial 
 period of Europe ; and the existing great interior ice-plateau 
 of Greenland, enormous as it is, must be considered as but the 
 remnant of a mass which was -incalculably greater, and to 
 which there is no parallel at the present time, excepting within 
 the Antarctic Circle. 
 
 And later on, in my book, "Scrambles among the Alps," 
 1871, pages 246, 247 : ' 
 
 The interior of Greenland appears to be absolutely covered 
 by a glacier between 68° 30-70° north latitude. ... On two 
 occasions, in 1867, I saw, at a glance, at least 6,000 square 
 miles of it from the summits of small mountains on its out- 
 skirts. Hot a single peak or ridge was to be seen rising above, 
 nor a single rock reposing upon the ice. The country was 
 completely covered up by glaciers ; all was ice, as far as the eye 
 could see. . . . This vast ice-plateau, although smaller than it 
 was in former times, is still so extensive that the whole of the 
 glaciers of the Alps might be merged into it without its bulk 
 being perceptibly increased. 
 
 In 1872 I again traveled in northwestern Greenland, and 
 by ascending various lofty mountains saw more of the " inland 
 ice"; and in the "Alpine Journal" for 1873, page 220, I 
 wrote : 
 
 From all the principal summits you perceive the vast gla- 
 cier-clad interior of the country, stretching from north to 
 south in an unbroken line, with a crest as straight as a sea- 
 horizon. There are no marks upon it which enable one to cal- 
 culate bhe altitude to which it rises, or the distance to which 
 it extends. But having now seen it from several elevated and 
 widely separated positions, as I find that its summit-line always 
 appears lofty, even from the highest mountains which I have 
 ascended, my impression is that its height is generally not less 
 
THE GLACIERS OF GREENLAND. 85 
 
 than 8,000 feeft, and in some places, perhaps, surpasses 10,000 
 feet. ... 
 
 On ascending hills on the outskirts I again had extiensive 
 views to the east, finding the land, as before, absolutely cov- 
 ered by glaciers. From the nearest parts to the farthest dis- 
 tance that could be seen, the whole of the ice was broken up 
 into seracs. It was almost everywhere riven and fissured in a 
 most extreme manner, and it was obviously totally impracti- 
 cable for sledges. . . . 
 
 From the repeated views of the interior which had been 
 seen from the coast mountains, it was clear that all this part 
 of Greenland, except the fringe of land on the Davis Strait 
 side, was absolutely covered by snow and ice, and that the in- 
 terior was not broken up in those latitudes as I had conjectured 
 it might be. . . . 
 
 This vast glacier is the largest continuous mass of ice at 
 present known. All the glaciers of the Alps combined are as 
 nothing to it, and the greatest of those in the Himalayas are 
 mere dwarfs in comparison. At Jakobshavn the bergs floating 
 away were often from 700 to 800 feet thick, and this is the only 
 information at present possessed of its depth. The angle at 
 which its surface rises toward the east is very slight, being 
 seldom so much as 8°, and generally much less ; while in some 
 places there are considerable depressions, and lakes are formed 
 in consequence. . . . 
 
 Mount Kelertingonit was 6,800 feet high, and there was a 
 grand and most interesting view from its summit in all direc- 
 tions. Southward it commanded the whole breadth of the 
 Noursoak Peninsula, and extended over the Waigat Strait to 
 the lofty island of Disco ; westward it embraced the western 
 part of the Noursoak Peninsula, with Davis Strait beyond ; 
 northward it passed right over the TJmenak Fiord (some thirty 
 miles wide) to the Black Hook Peninsula ; to the northeast it 
 was occupied by the fiord, with its many imposing islands and 
 islets, surrounded by innumerable icebergs streaming away 
 from the inland ice ; and in the east, extending from north- 
 east to southeast, over well-nigh 90° of the horizon, there was 
 the inland ice itself — presenting the characteristic features 
 ■which have been mentioned in the earlier papers. The south- 
 
86 THE ICE AGE IN NOETH AMERICA. 
 
 ern part of the view of the inland ice, as seen from Kelertin- 
 gouit, OTerlapped the northern part of it as seen on former 
 occasions, while northward it extended to at least 71" 15' north 
 latitude, so I had now viewed the section of the interior be- 
 tween 68° 30' and 71° 15', equal to 190 English miles, and had 
 everywhere found a straight, unbroken crest of snow-covered 
 ice, concealing the land so absolutely that not a single crag 
 appeared above its surface. 
 
 The height of this straight, unbroken crest of snow was 
 now the object of attention — the principal object for which 
 the ascent was made. On bringing the theodolite to bear upon 
 it, I found that it appeared to be slightly depressed below my 
 station ; but, as it was distant more than one hundred miles, 
 it was only lower in appearance and not in reality. On the 
 assumption that it was no more than one hundred miles dis- 
 tant, after making allowance for the refraction and curvature 
 of the earth, its height was found to be considerably in excess 
 often thousand feet* 
 
 Northward from this point explorations have been carried 
 on incessantlj"- since the middle of the last century begin- 
 ning with the expeditions of Drs. Kane and Hayes between 
 the years 1855 and 1862. These remarkable men were 
 associated from 1853 to 1855, in the second Grinnell Expe- 
 dition in search of Sir John Franklin, which succeeded in 
 exploring the coast on the east side of Smith Sound from 
 Cape Alexander, in latitude 78°, to Washington Land, in 
 latitude 80°; while in 1861 and 1862 Dr. Hayes conducted 
 an independent expedition to Lady Franklin Bay, in lati- 
 tude 82°, and resurveyed portions of his former field. 
 
 In the neighborhood of Cape Dudley Digges, about lati- 
 tude 76°, Dr. Kane's party encountered a glacier which he 
 describes as follows: 
 
 This glacier was about seven miles across at its "de- 
 bouche" ; it sloped gradually upward for some five miles back. 
 
 *" Explorations in Greenland," "Clioioe Literature," 1884, pp. 170, 
 808. 
 
THS GLACIERS OF GREENLAND. 87 
 
 and then, following the irregularities of its rocky substructure, 
 suddenly became a steep crevassed hill, ascending in abrupt 
 terraces. Then came two intervals of less rugged ice, from 
 which the glacier passed into the great mer de glace. 
 
 On ascending a high, craggy hill to the northward, I had a 
 sublime prospect of this great frozen ocean, which seems to 
 form the continental axis of Greenland — a vast, undulating 
 plain of purple-tinted ice, studded with islands, and absolutely 
 gemming the horizon with the varied glitter of sun-tipped 
 crystal. 
 
 The discharge of water from the lower surface of the gla- 
 cier exceeded that of any of the northern glaciers except that 
 of Humboldt and the one near Etah. One torrent on the side 
 nearest me overran the ice-foot from two to five feet in depth, 
 and spread itself upon the floes for several hundred yards ; 
 and another, finding its outlet near the summit of the glacier, 
 broke over the rocks and poured in cataracts upon the beach 
 below.* 
 
 Between "Wolstenholme Sound and Murchison Strait, 
 about latitude 76° 60', Tyndall Glacier comes down to the 
 sea in a broad current ten or twelve nailes in width ; while 
 twenty or twenty-five miles to the north, on Northumberland 
 Island, a curious glacier is described by Kane, which he 
 calls a " hanging glacier," and named after his brother John. 
 " It seemed," he says, " as if a caldron of ice inside the 
 coast-ridge was boiling over, and throwing its crust in huge 
 fragments from the overhanging lip into the sea below. The 
 glacier must have been eleven hundred feet high ; but even 
 at its summit we could see the lines of viscous movement." f 
 
 Upon another point in this island a glacier was encount- 
 ered which affords Dr. Kane opportunity to remark upon 
 some points not often noticed. The party had encamped on 
 a low beach at the foot of a moraine which came down be- 
 tween precipitous cliffs of surpassing wildness. While there, 
 he says : 
 
 * "Arctic Explorations in the Years 1853, 1854, 1855," vol. ii, pp. 270-272. 
 \ Ibid., pp. 259, 260. 
 
88 THE ICE AGE m NORTH AMEEICA. 
 
 I was greatly interested by a glacier that occupied the head 
 of the moraine. It came down abruptly from the central pla- 
 teau of the island, with an angle of descent of more than sev- 
 enty degrees. I have never seen one that illustrated more 
 beautifully the viscous or semi-solid movement of these masses. 
 Like a well-known glacier of the Alps, it had two planes of 
 descent : the upper nearly precipitous for about four hundred 
 feet from the summit ; the lower of about the same height, but 
 with an angle of some fifty degrees ; the two communicating 
 by a slightly inclined platform perhaps half a mile long. This 
 ice was unbroken through its entire extent. It came down from 
 the level of the upper country, a vast icicle, with the folds or 
 waves impressed upon it by its onward motion undisturbed by 
 any apparent fracture or crevasse. Thus it rolled onward over 
 the rugged and contracting platform below, and thence poured 
 its semi-solid mass down upon the plain. Where it encount- 
 ered occasional knobs of rock it passed round them, bearing 
 still the distinctive marks of an imperfect fluid obstructed in 
 its descent ; and its lower fall described a dome, or, to use 
 the more accurate simile of Forbes, a great outspread clam- 
 shell of ice. 
 
 It seemed as if an interior ice-lake was rising above the 
 brink of the cliffs that confined it. In many places it could 
 be seen exuding or forcing its way over the very crest of the 
 rocks, and hanging down in huge icy stalactites seventy and 
 one hundred feet long. These were still lengthening out by 
 the continuous overflow, some of them breaking off as their 
 weight became too great for their tenacity, others swelling by 
 constant supplies from the interior, but spitting off fragment- 
 ary masses with an unremitting clamor. The plain below 
 these cataractine glaciers was piling up with the debris, while 
 torrents of the melted rubbish found their way, foaming and 
 muddy, to the sea, carrying gravel and rocks along with them. 
 
 These ice-cascades, as we called them, kept up their din the 
 whole night, sometimes startling us with a heavy booming 
 sound, as the larger masses fell, but more generally rattling 
 away like the random fires of a militia parade. On examining 
 the ice of which they were made up, I found grains of neve 
 larger than a walnut ; so large, indeed, that it was hard to re- 
 
TEE OLACTERS OF GEEENLAITD. 89 
 
 alize that they could be formed by the ordinary granulating 
 processes of the winter snows. My impression is, that the sur- 
 face of the plateau-ice, the mer de glace of the island, is made 
 up of these agglomerated nodules, and that they are forced out 
 and discarded by the advance of the more compact ice from 
 higher levels.* 
 
 The winter of 1853 and 1854 was spent by Dr. Kane in Van 
 Rensselaer Harbor, in latitude 78° 60'. From this point Dr. 
 Hayes and a small party were sent inland for the purpose of 
 securing, if possible, some game to eke out their ship-sup- 
 plies of food. They reported that, " after penetrating the 
 interior about ninety miles, their progress was arrested by a 
 glacier four hundred feet high, and extending to the north 
 and west as far as the eye could reach." On his second ex- 
 pedition, in 1860, Dr. Hayes penetrated this same region 
 again, starting from Port Foulke, about twenty miles to the 
 southwest — venturing, this time, some distance out on the 
 surface of the glacier. The following is his own vivid de- 
 scription of the ice-field, beginning ivith the narrative of his 
 first expedition. 
 
 At length we emerged upon a broad plain or valley, wider 
 than any we had yet seen, in the heart of which reposed a 
 lake about two miles in length by half a mile in width, over 
 the transparent, glassy surface of which we walked. On either 
 side of us rose rugged bluffs, that stretched off into long lines 
 of hills, culminating in series in a broad-topped mountain- 
 ridge, which, running away to right and left, was cut by a gap 
 several miles wide that opened directly before us.. Immediately 
 in front was a low hill, around the base of which flowed upon 
 either side the branches of the stream which we had followed. 
 Leaving the bed of the river just above the lake, we ascended 
 to the top of this hillock ; and here a sight hurst upon us, 
 grand and imposing beyond any power of mine adequately to 
 describe. From the rocky bed, only a few miles in advance, a 
 sloping wall of pure whiteness rose to a broad level plain of ice 
 
 * " Arctic Explorations," vol. i, pp. 334-336, 
 
90 THE IG.E AGE J-tf NORTH AMERICA. 
 
 which, apparently boundless, stretched away toward the un- 
 known east. It was the great iner de glace of the Ai'ctic Con- 
 tinent. 
 
 At any subsequent period of the cruise this sight would 
 have less impressed me ; but I had never, except in the dis- 
 tance, seen a glacier. Here before us was, in reality, the 
 counterpart of the river-system of other lands. From behind 
 the granite hills the congealed drainings of the interior water- 
 sheds, the atmospheric precipitations of ages, were moving as 
 a solid though plastic mass, down through every gap in the 
 mountains, swallowing up the rocks, filling the valleys, sub- 
 merging the hills — an onward, irresistible, crystal tide, swell- 
 ing to the ocean. Cutting the surface were many vertical 
 crevasses, or gutters, some of great depth, which had drained 
 off the melted snow. 
 
 It was midnight when we made our approach. The sun 
 was several degrees beneath the horizon, and afforded us a 
 faint twilight. Stars of the second magnitude were dimly visi- 
 ble in the northern heavens. When we were within about 
 half a mile of the icy wall, a brilliant meteor fell before us, 
 and, by its reflection upon the glassy surface beneath, greatly 
 heightened the effect of the scene ; while loud reports, like 
 distant thunder or the booming of artillery, broke at intervals 
 from the heart of the frozen sea. 
 
 Upon close inspection we found the face of the glacier to 
 ascend at an angle of from thirty to thirty-five degrees. At its 
 base lay a high snow-bank, up which we clambered about sixty 
 feet ; but beyond this the ice was so smooth as to defy our 
 efforts. The mountains, which stood like giant gate-posts on 
 either side, were overlapped and partially submerged by the 
 glacier. From the face of this a multitude of little rivulets 
 ran down the gutters already mentioned, or gurgled from be- 
 neath the ice, and formed, on the level lands below, a sort of 
 marsh, not twenty yards from the icy wall. Here grew, in 
 strange contrast, beds of green moss ; and in these, tufts of 
 dwarf willows were twining their tiny arms and rootlets about 
 the feebler flower-growths : and there, clustered together, 
 crouched among the grass, aijd sheltered by the leaves, and 
 feeding on the bed of lichens, I found a white-blossomed draba 
 
THE QLAGIERS OF GREENLAND. 91 
 
 which would have needed only a lady's thimble for a flower- 
 pot, and a white chickweed. Dotting the few feet of green 
 around me were seen the yellow blossoms of the more hardy 
 poppy, the purple potentilla, and the white, purple, and yellow 
 saxifrages. 
 
 This little oasis was literally imbedded in ice. The water 
 which had flowed through it had frozen in the holes, and 
 spread itself out in a crystal sheet upon the rocks and stones 
 around. A few specimens of the tiny blossoms were laid in 
 my note-book, a sprig of heather and a saxifrage were stuck in 
 my button-hole, and with these souvenirs we left this garden- 
 spot which the glacier was soon to cover forever from human 
 eyes. . . . 
 
 In the autumn of 1860 I was favored with an opportunity 
 to make a more important exploration of this great mer de 
 glace, having from my winter harbor at Port Foulke ascer- 
 tained that it had broken through the mountain-chain at the 
 head of the bay in which my harbor was situated, and was 
 there approaching the sea. Up this glacier, which had thus 
 forced the rocky ramparts, I made my way with a small party 
 of men, attaining an altitude of about 5,000 feet, and extend- 
 ing my observations seventy miles from the coast. The jour- 
 ney possessed the more value that it was entirely novel as re- 
 gards the interior of Greenland. I was finally driven back by 
 a severe gale of wind, which, being accompanied by a sudden 
 fall of temperature, placed my party, for the time, in great 
 jeopardy, as my tent afforded no shelter ; but I had gone far 
 enough to determine, with some degree of accuracy, the char- 
 acter of the interior ; and the information thus acquired, in 
 connection with my journey with Mr. Wilson in 1853, as just 
 related furnishes an important addition to our knowledge of 
 the great glacier system of the Greenland Continent. Bast- 
 ward from the position attained on both of these journeys no 
 mountains were visible — nothing but a uniform inclined plane 
 of whiteness, a solid sea of ice, hundreds and hundreds of feet 
 in depth, steadily rising until lost in the distance against the 
 sky. A full description of the journey of 1860 has been pub- 
 lished in my "Open Polar Sea." 
 
 This vast body of ice, now known as Humboldt Glacier, is 
 
92 THE ICE AGE IN NORTH AMERICA. 
 
 the largest glacier known, being about sixty miles across, and 
 through at least one half of that extent discharging icebergs. 
 Like the glacier already spoken of as having broken through 
 the mountains near Port Foulke, this Humboldt Glacier has 
 overcome the mountain-barriers, and poured down into the 
 sea between Greenland and Washington Land, which latter is 
 probably an island, lying in the expansion of Smith Sound 
 (or Strait, as named by Dr. Kane), the water flowing to the 
 eastward of Washington Land being now entirely replaced by 
 the glacier. Prom Humboldt Glacier the face of the mer de 
 glace sweeps around behind the mountain-chain in a curve 
 toward Port Foulke. At the point reached by Mr. Wilson 
 and myself, the ice was breaking through the mountains, 
 nearly midway between these two extremes of the curve, and 
 •will, at some remote period, find its way into Smith Sound 
 through the tortuous valley which now forms the bed of Mary 
 Miuturn Eiver. South of Port Foulke the face of the mer de 
 glace forms a series of similar curves of greater or less extent, 
 and through all the great valleys of the Greenland coast-range, 
 glaciers discharge into Baffin Bay their streams of icebergs. 
 Several of these glaciers are from five to twenty miles across, 
 and those of Melville Bay are doubtless much more exten- 
 sive;* 
 
 This great Humboldt Glacier enters Peabody Bay from 
 the east, filling the whole space from latitude 79° to 80°. 
 There is, however, a vast movement of glacier-ice toward 
 this point from the southeast. The face of the Humboldt 
 Olacier is described by Dr. Kane as everywhere, for a 
 <listance of more than sixty miles, an " abrupt and threat- 
 ening precipice, only broken by clefts and deep ravines, 
 giving breadth and interest to its wild expression." f The 
 party which first saw this majestic ice-front were com- 
 pelled to traverse its entire breadth on the ice which had 
 formed outside it in the months of September and October. 
 A chief peril of their situation arose from the discharging 
 
 * " An Arctic Boat-Journey," pp. 10-12, 377, 878. 
 f "Arctic Explorations," vol. i, p. 222. 
 
THE GLACIERS OF GBEENLAWD. 93 
 
 l)erg8 of the great glacier which broke up the ice for miles 
 around, at one time producing, directly under their tent; a 
 fissure in the ice on which they had camped for the night. 
 Repeatedly they were compelled to ferry themselves over 
 the cracks in the ice on the bay by rafts of ice. * 
 
 Kane gives his first impressions of this grand glacier in 
 the following vivid description : 
 
 I will not attempt to do better by florid description. Men 
 only rhapsodize about Niagara and the ocean. My notes speak 
 simply of the "long, ever-shining line of cliff diminished to a 
 well-pointed wedge in the perspective " ; and, again, of " the 
 face of glistening ice, sweeping in a long curve from the low 
 interior, the facets in front intensely illuminated by the sun." 
 But this line of cliff rose in a solid, glassy wall 300 feet above 
 the water-level, with an unknown, unfathomable depth below 
 it ; and its curved face, sixty miles in length from Cape Agas- 
 siz to Cape Forbes, vanished into unknown space at not more 
 than a single day's railroad-travel from the pole. The interior, 
 with which it communicated and from which it issued, was 
 an unsurveyed mer de glace — an ice-ocean, to the eye, of boundr 
 less dimensions. 
 
 It was in full sight — the mighty crystal bridge which con- 
 nects the two continents of America and Greenland. I say 
 continents ; for Greenland, however insulated it may ulti- 
 mately prove to be, is in mass strictly continental. Its least 
 possible axis, measured from Cape Farewell to the line of this 
 glacier, in the neighborhood of the eightieth parallel, gives a 
 length of more than 1,200 miles, not materially less than that 
 of Australia from its northern to its southern cape. 
 
 Imagine, now, the center of such a continent, occupied 
 through nearly its whole extent by a deep, unbroken sea of 
 ice that gathers perennial increase from tlie water-shed of vast 
 snow-covered mountains and all the precipitations of its atmos- 
 phere upon its own surface. Imagine this, moving onward 
 like a great glacial river, seeking outlets at every fiord and 
 valley, rolling icy cataracts into the Atlantic and Greenland 
 
 * "Arctic Explorations," vol. i, p. 135. 
 
M THE ICE AGE IN NORTH AMERICA. 
 
 seas ; and, having at last reached the northern limit of the 
 land that has borne it up, pouring out a mighty frozen tor- 
 rent into unknown arctic space. 
 
 It is thus, and only thus, that we must form a just concep- 
 tion of a phenomenon like this great glacier. I had looked in 
 my own mind for such an appearance, should I ever be fortu- 
 nate enough to reach the northern coast of Greenland. But, 
 now that it was before me, I could hardly realize it. I had 
 recognized, in my quiet library at home, the beautiful analo- 
 gies which Forbes and Studer have developed between the 
 glacier and the river. But I could not comprehend, at first, 
 this complete substitution of ice for water. 
 
 It was slowly that the conviction dawned on me that I was 
 looking upon the counterpart of the great river-system of Arc- 
 tic Asia and America. Yet here were no water-feeders from 
 the south. Every particle of moisture had its origin within 
 the polar circle, and had been converted into ice. There were 
 no vast alluvions, no forest or animal traces borne down by 
 liquid torrents. Here was a plastic, moving, semi-solid mass, 
 obliterating life, swallowing rocks and islands, and plowing 
 its way with irresistible march through the crust of an invest- 
 ing sea.* 
 
 The following summer Dr. Kane visited the scene again, 
 and gives many additional particulars : 
 
 I had not [he writes] realized fully the spectacle of this 
 stupendous monument of frost. I had seen it for some hours 
 hanging over the ice like a white-mist cloud, but now it rose 
 up before me clearly defined and almost precipitous. The 
 whole horizon, so vague and shadowy before, was broken by 
 long lines of icebergs ; and as the dogs, cheered by the cries 
 of their wild drivers, went on, losing themselves deeper and 
 deeper in the labyrinth, it seemed like closing around us the 
 walls of an icy world. They stopped at last ; and I had time, 
 while my companions rested and fed, to climb one of the high- 
 est bergs. The atmosphere favored me : the blue tops of 
 Washington Land [to the north] were in full view, and, 
 
 * "Arctic Explorations," vol. i, pp. 225-228. 
 
THE GLACIERS OF GREENLAND. 95 
 
 losiug itself in a dark water-cloud, the noble head-land of John 
 Barrow. 
 
 The trend of this glacier is a few degrees to the west of 
 north. We followed its face afterward, edging in for the 
 Greenland coast, about the rocky archipelago which I haye 
 named after the Advance. From one of these rugged islets, 
 the nearest to the glacier which could be approached with any- 
 thing like safety, I could see another island, larger and closer 
 in shore, already half covered by the encroaching face of the 
 glacier, and great masses of ice still detaching themselves and 
 splintering as they fell upon that portion which protruded. 
 Kepose was not the characteristic of this seemingly solid mass ; 
 every feature indicated activity, energy, movement. 
 
 The surface seemed to follow that of the basis-country over 
 which it flowed. It was undulating about the horizon, but 
 as it descended toward the sea it represented a broken plain 
 with a general inclination of some nine degrees, still dimin- 
 ishing toward the foreground. Crevasses, in the distance mere 
 wrinkles, expanded as they came nearer, and were crossed 
 almost at right angles by long, continuous lines of fracture 
 parallel with the face of the glacier. 
 
 These lines, too, scarcely traceable in the far distance, 
 widened as they approached the sea until they formed a gigan- 
 tic stairway. It seemed as though the ice had lost its support 
 below, and that the mass was let down from above in a series 
 of steps. Such an action, owing to the heat derived from the 
 soil, the excessive surface-drainage, and the constant abrasion 
 of the sea, must in reality take place. My note-book may 
 enable me at some future day to develop its details. I have 
 referred to this as the escaladed structure of the arctic gla- 
 cier. 
 
 The indication of a great propelling agency seemed to be 
 just commencing at the time I was observing it. These split- 
 off lines of ice were evidently in motion, pressed on by those 
 behind, but still widening their fissures, as if the impelling 
 action was more and more energetic nearer the water, till at 
 last they floated away in the form of icebergs. Long files of 
 these detached masses could be traced slowly sailing off into 
 the distance, their separation marked by dark parallel shadows 
 
96 THE IGE AGE IN NORTH AMEBIC A. 
 
 — ^broad and spacious avenues near the eye, but narrowed in 
 the perspective to mere lines. A more impressive illustration 
 of the forces of Nature can hardly be conceived. . . . 
 
 The frozen masses before me were similar in structure to 
 the Alpine and Norwegian ice-growths. It would be foreign 
 to the character of this book to enter upon the discussion 
 which the remark suggests ; but it will be seen by the sketch, 
 imperfect as it is, that their face presented nearly aU the char- 
 acteristic features of the Swiss Alps. The "overflow," as I 
 have called the viscous overlapping of the surface, was more 
 clearly marked than upon any Alpine glacier with which I am 
 acquainted. When close to the island-rocks, and looking out 
 upon the upper table of the glacier, I was struck with the 
 homely analogy of the batter-cake spreading itself out under 
 the ladle of the housewife, the upper surface less affected by 
 fi'iction, and rolling forward in consequence. 
 
 The crevasses bore the marks of direct fracture and the 
 more gradual action of surface-drainage. The extensive water- 
 shed between their converging planes gave to the icy surface 
 most of the hydrographic features of a river-system. The ice- 
 born rivers which divided them were margined occasionally 
 with spires of discolored ice, and generally lost themselves in 
 the central areas of the glacier before reaching its foreground. 
 Occasionally, too, the face of the glacier was cut by vertical 
 lines, which, as in the Alpine growths, were evidently outlets 
 for the surface-drainage. Everything was, of course, bound 
 in solid ice when I looked at it ; but the evidences of torrent- 
 action were unequivocal, and Mr. Bonsall and Mr. Morton, at 
 their visits of the preceding year, found both cascades and 
 water-tunnels in abundance. 
 
 The height of this ice-wall at the nearest point was about 
 three hundred feet, measured from the water's edge ; and the 
 unbroken right line of its diminishing perspective showed 
 that this might be regarded as its constant measurement. It 
 seemed, in fact, a great icy table-land, abutting with a clean 
 precipice against the sea. This is, indeed, characteristic of 
 all those arctic glaciers which issue from central reservoirs, or 
 mers de glace, upon the fiords or bays, and is strikingly in con- 
 trast with the dependent or hanging glacier of the ravines. 
 
THE GLACIERS OF GREENLAND. 97 
 
 where every line and furrow and chasm seems to indicate the 
 morement of descent and the mechanical disturbances which 
 have retarded it. 
 
 I have named this great glacier after Alexander von Hum- 
 boldt, and the cape which flanks it on the Greenland coast 
 after Professor Agassiz. 
 
 The point at which this immense body of ice enters the 
 land of Washington gives even to a distant view impressive 
 indications of its plastic or semi-solid character. No one could 
 resist the impression of fluidity conveyed by its peculiar mark- 
 ings. I have named it Cape Forbes, after the eminent crystal- 
 ologist whose views it so abundantly confirms. 
 
 As the surface of the glacier receded to the south, its face 
 seemed broken with piles of earth and rock-stained rubbish, 
 till far back in the interior it was hidden from me by the slope 
 of a hill. Still beyond this, however, the white blink or glare 
 of the sky above showed its continued extension; 
 
 It was more difficult to trace this outline to the northward, 
 on account of the immense discharges at its base. The talus 
 of its descent from the interior, looking far off to the east, 
 ranged from seven to fifteen degrees, so broken by the crevasses, 
 however, as to give the effect of an inclined plane only in the 
 distance. A few black knobs rose from the white snow, like 
 islands from the sea. 
 
 The general configuration of its surface showed how it 
 adapted itself to the inequalities of the basis-country beneath. 
 There was every modification of hill and valley, just as upon 
 land. Thus diversified in its aspect, it stretches to the north 
 till it bounds upon the new land of Washington, cementing 
 into one the Greenland of the Scandinavian Vikings and the 
 America of Columbus.* 
 
 Much less is known concerning the' eastern coast of Green- 
 land than about the western coast. For a long time it was 
 supposed that there might be a considerable population in 
 the lower latitudes along the eastern side. But that is now 
 proved to be a mistake. The whole coast is very inhos- 
 
 * "Arctic Explorations," vol. ii, pp. 146-168. 
 
98 THE IGE AGE IN NORTH AMERICA. 
 
 pitable and diflScult of approach. From latitude 65° to lati- 
 tude 69° little or nothing is known of it. In 1822-'23 
 Seoresby, Cleavering, and Sabine, hastily explored the coast 
 from latitude 69° to 76°, and reported numerous glaciers 
 descending to the sea-level through extensive fiords, from 
 which immense icebergs float out and render navigation dan- 
 gerous. In 1869 and 18T0 the second Korth Gennan Expe- 
 dition partially explored the coast between latitude 73° and 
 77°. Mr. Payer^ an experienced Alpine explorer, who ac- 
 companied the expedition, reports the country as much 
 broken, and the glaciers as " subordinated in position to the 
 higher peaks, and having their moraines, both lateral and 
 terminal, like those of the Alpine ranges, and on a still 
 grander scale." Petermann Peak, in latitude 73°, is reported 
 as 13,000 feet high. Captain Koldewey, chief of the expe- 
 dition, found extensive plateaus on the mainland, in latitude 
 75°, to be " entirely clear of snow, although only sparsely 
 covered with vegetation." The mountains in this vicinity, 
 also, rising to a height of more than 2,000 feet, were free 
 from snow in the summer. Some of the fiords in this vicin- 
 ity penetrate the continent through several degrees of longi- 
 tude. An interesting episode of this expedition was the 
 experience of the crew of the ship Hansa, which was caught 
 in the ice and destroyed. The crew, however, escaped by 
 encamping on the ice-floe which had crushed their ship. 
 From this, as it slowly floated toward the south through sev- 
 eral degrees of latitude, they had opportunity to make many 
 important observations upon the continent itself. As viewed 
 from this unique position, the coast had the appearance every- 
 where of being precipitous, with mountains of considerable 
 height rising in the background, from which numerous small 
 glaciers descended to the sea-level. 
 
 In 1888 Dr. F. Nansen, with Lieutenant Sverdrup and 
 four others, was left by a whaler on the ice-pack bordering 
 the east of Greenland about latitude 65°, and in sight of the 
 coast. For twelve days the party was on the ice-pack float- 
 ing south, and so actually reached the coast only about lati- 
 
THE GLACIERS OP QUEENLAND. 99 
 
 tude 64°. From this point they attempted to cross the inland 
 ice in a northwesterly direction toward Christianshaab. They 
 soon reached a height of Y,000 feet, and were compelled by 
 severe northerly storms to diverge from their course, taking 
 a direction more to the west. The greatest height attained 
 was 9,500 feet, and the party arrived on the western coast at 
 Ameralik Fiord, a little south of Gotthaab, about the same 
 latitude at which they entered. 
 
 In 1892, and again in 1895, Lieutenant Robert E. Peary 
 set out from Inglefield Gulf (latitude 77° 40'), and traveling 
 in a northeasterly direction for a distance of something over 
 iive hundred miles, crossed the Greenland ice-sheet, and came 
 out near latitude 82° and longitude 40°. He succeeded in 
 i*>apping a considerable portion of the northern coast, and 
 in demonstrating that Greenland is really an island, with 
 smaller islands to the north. Glaciers were found here flow- 
 ing to the north, while there was much vegetation supporting 
 herds of musk-ox and other forms of life. The interior ice 
 was found to be of a pretty uniform height, ranging from 
 3,000 to 9,000 feet above tide. Indeed, the conditions did 
 not materially differ from tliose found by Nansen fifteen de- 
 grees farther south. 
 
 In 1907 M. Ericbsen, in charge or a Danish expedition, 
 pushed his vessel up the east coast of Greenland to 77° 
 north latitude, near Cape Bismarck, from which point he 
 explored the territory northward to Independence Bay, 
 thus completing the survey of the continent. But although he 
 lost his life in the effort, his notes were complete and showed 
 to the surprise of all that beyond the 78th parallel the coast 
 trended northeast instead of northwest, extending towards 
 Spitsbergen until the opening between the Arctic and Atlantic 
 Oceans is narrowed to 240 miles, only one-third the width 
 that had been formerly supposed to exist. 
 
 In the summer of 1909, both Frederick A. Cook and Rob- 
 ert E. Peary laid claims to having reached the north pole, 
 both explorers claiming to have set out from the northern 
 part of Grant Land, Cook in 1908 and Peary in 1909. Both 
 
100 THE ICE AGE IX XORTH AMERICA. 
 
 agree in their reports that there was smooth ice beyond the 
 88th parallel, in which rapid traveling could be accomplished, 
 Peary alleging that he made the last 130 geographical miles 
 in five forced marches, reaching the pole April 6, 1909. All 
 was ice with no land in sight. Temperatures ranged from 
 12-° to -33° with cloudless sky. The return journey of 413 
 geographical miles was made in 16 days. A single imperfect 
 sounding disclosed the existence of a deep ocean in close 
 proximity to the pole. The reports of Cook, made previously 
 to those of Peary, revealed almost identical conditions. 
 
 Among the most instructive observations upon the Green- 
 land glaciers were those made in 1880 by Dr. N. O. Hoist of 
 the Swedish Geological Survey. These were made on the 
 Frederickshaab Glacier in latitude 62° 32', and have a most 
 important bearing upon the mode of the accumulation of 
 moraines of all sorts. He found extensive deposits of both 
 englaeial and subglacial drift, respectively characterized by 
 angular and glaciated stones and bowlders. The largest 
 accumulation of superglacial drift, which had been englaeial, 
 was observed on the southern edge of the lobe. The drift 
 covering the ice-surface here, as exposed by the ablation or 
 superficial melting, was ascertained to extend along a distance 
 of nearly twelve miles, and to reach half a mile to a mile and 
 a half upon the ice. The quantity and upper limit of the 
 superglacial drift at this locality are given by him as follows: 
 
 Its thickness is always greatest near land, but here it is 
 often quite difficult to estimate its actual thickness, as it 
 sometimes forms a compact covering, only in some fissures 
 showing the underlying ice. This uneven thickness of moraine 
 cover offers to the ice a proportionally varying protection 
 against the sun. It thus happens that the unequal thawing 
 moulds the underlying surface of the ice into valleys and hills, 
 the latter sometimes arising to a height of fifty feet above 
 the adj acent valley, and being so densely covered with morainic 
 material that this completely hides the ice core, which, how- 
 ever, often forms the main part of the hill. 
 
THE GLACIERS OF GREENLAND. 101 
 
 Farther in on the ice the moraine gradually thins out. At 
 the locality just referred to the moraine cover, 3,000 feet 
 from land, measured several inches in depth; still the ice was 
 seen in some bare spots. Beyond 4,000 feet from land the 
 moraine formed no continuous cover, and at 8,300 feet it 
 ceased entirely, with a perceptible limit against clear ice. 
 Only some scattered spots of sand and gravel were met with 
 even a few hundred feet farther in on the ice. 
 
 The average thickness of the moraine taken across its 
 entire width near its eastern end is estimated at from one to 
 two feet. The limit between the moraine cover and the pure 
 ice is always located at a considerable though varying ele- 
 vation above the edge of the inland ice. In the instance of 
 the above mentioned moraine it varied between 200 feet and 
 500 feet. 
 
 The ice within 100 feet of its borders invariably presents 
 a slope towards the border, though generally not so steep, as 
 to render the ascent at all difficult. Farther in, the slope is 
 much less marked, though there appears to exist a general 
 rising towards the east, while the surface everj^where presents 
 vast undulations. The border of the ice appears to have 
 retreated quite recently in many places; in others it had 
 evidently advanced .... On the surface the inland ice 
 either presented the appearance of a compact mass of coarse 
 crystallinic texture, reminding one of the grains of common 
 rock candy, or else it is honeycombed by the solar heat and 
 shows intersecting systems of parallel plates, apparently 
 the remnants of large ice crystals, often several inches long, 
 which have wasted away, only leaving the frame as it were, 
 on which they were built. These plates or tablets are highly 
 mirroring, reflecting the solar rays in all directions, depending 
 on the position of each individual crystal.* 
 
 These observations respecting the height of the englacial 
 till in the ice correspond closely to those of Professor Russell 
 on the Malaspina Glacier in Alaska, and those of Professor 
 
 * "American Naturalist," vol. xxii, pp. 589-598 and 705-713, July and 
 August, 1888. 
 
102 THE ICE AGE IN NORTH AMERICA. 
 
 T. C. Chamberlin, hereafter to be noted, in northern Green- 
 land. 
 
 Some most remarkable facts concerning the termination 
 of numerous glaciers in northern Greenland and in Grinnell 
 Land and Ellsmere Land on the other side of Smith Sound are 
 reported by Professor Chamberlin and by General A. W. 
 Greely.* In both these regions the glaciers often terminate 
 in perpendicular, or projecting ice cliffs. So extensive and 
 marked are these in Ellsmere Land that they were termed the 
 "Chinese Wall." They extend across the country in an 
 east and west direction and form an escarpment from 200 to 
 300 feet high. Over the crest of the wall appear the snow 
 fields and snow covered mountains where the glacier has its 
 source. 
 
 The explanation of this peculiar phenomenon is to be 
 found partly in the fact that the upper strata of the ice 
 move faster than the lower, tending to form a "breaker" 
 in the ice, such as appears on the crest of an incoming wave. 
 Partly also, as suggested by Professor Chamberlin, because 
 the low angle at which the sun's rays strike the ice causes 
 them to melt the lower dirt laden strata which attract the 
 heat, faster than the purer strata found near the top of the 
 ice. 
 
 *A. W. Greely, "Report of Proceedings of U. S. Expedition to Lady 
 Franklin Bay," Washington, 1888, vol. i, pp. 274-296. 
 
Fin. 34 — Sea marein of rornolJ Glacier, Oreonland. (Tarr). 
 
 Fig. 35 — Cllacler in North Greenland, showing the upper strata of ice rolling over like 
 breakers. fPhotosraphed l>y Chamberlfn). 
 
CHAPTEE V. 
 
 GLACIERS IN OTHER PAETS OF THE WOELD. 
 
 Befoee finally concentrating oiir attention upon the 
 ancient glaciated area of North America, it will be profit- 
 able to take a glance at existing glaciers in other parts of 
 the world. As is well known, glaciers still envelop the 
 island of Spitzbergen and linger in the mountains of Nor- 
 way and Sweden, of central Europe, and of southern Asia. 
 Vast glaciers also come down to the sea-level in Patagonia, 
 and appear higher up upon the mountains of southern Chili. 
 The mountains of New Zealand* likewise contain numerous 
 groups of glaciers nearly as extensive as those of the Alps. 
 The so-called Antarctic Continent would seem to he covered 
 with one vast sheet of ice pressing outward, and breaking off 
 into immense icebergs. 
 
 The glaciers of the Alps have been so frequently described 
 that only a few words need be devoted to them here. It is 
 estimated that there are as many as four hundred glaciers in 
 the Alpine range between Mont Blanc and Tyrol, and that, 
 all told, they cover an area of more than 1,400 square miles. 
 In many places the ice is estimated to be 600 feet in thick- 
 ness. The Aletsch Glacier, in the Bernese Oberland, is the 
 longest in the Alps, being not far from twenty miles. Many 
 others are ten miles or more in length, ind are often in certain 
 portions of their course from one mile to one mile and a half 
 wide. The line of perpetual snow in the Alps is something 
 
 * See Whitney's " Climatic Changes," pp. 269-274, to which we are largely 
 indebted for the facts presented in this chapter. 
 
GLACTERS IX OTHER PARTS OF TEE WORLD. 105 
 
 more than 7,500 feet above the sea. The glaciers extend 
 from i,000 to 5,000 feet lower, though the "limit is by no 
 
 Fig 36 — AIorterat=*ch Glacier, Orisons Alps. This ijlacier advances about seven inches 
 perjear. Centurits ago chalets stood a mile farther up the valle,y. In 18(J8 frag- 
 ments of these ancient dwellings were \vashed out from underneath "the ice. 
 
 means constant from year to year. " M. Forel reports, from 
 the data which he has collected with nmch care, that there 
 have been in this centnry five period.s in the Alpine glaciers : 
 of enlargement, from 1800 (?) to 1815 ; of diminntion, from 
 1815 to 1830 ; of enlargement, from 18.30 to 1845 ; of dimi- 
 nution, from 1845 to 1875 ; and of enlargement, again, from 
 1875 onward. He I'emarks further that these periods cor- 
 respond with those deduced by Mr. C. Lang for the variations 
 for the precipitations and temperature of the air ; and, con- 
 sequently, that the enlargement of the glaciers has gone for- 
 
106 
 
 THE ICE A(iE IX yORTH AMERICA. 
 
 ward in the cold and rainy period, and tbe diminution in 
 the warm and the drv (' Archives Sci. Phys. Xat.,' May 15, 
 1886, p. 503)."* 
 
 The iflaciers of Scandinavia, with their suow-tields, are 
 estimated to cover a s]>ace of about 5.011(1 sqiiare miles. The 
 
 Fu;. 37.— Tho Svarli^en (iiacitr on tin; \\e*t coaf^t of Norway, jiit^t withiu the Arctic cir- 
 cle, at the head of a liord ten miles from the ocean. Mouth of the slaciei- one mile 
 wide, and a quarter of a mile back from the water. Terminal moraine in front. 
 (Photographed by Dr. L. C. Warner, i 
 
 mountains are less lofty tlian the Alps, the greatest altitude 
 being about 8,500 feet. But the more northern latitude and 
 the moist climate are favorable to the production of glaciers. 
 The largest single siiow-tield is that of Justedal, in latitude 
 fi2°, occupying a plateau about 5,000 feet above the sea-level, 
 and an area of 580 square miles. From this plateau twenty- 
 four glaciers descend through the gorges leading toward the 
 North German Sea, the largest of which is about five miles 
 long and three qiiarters of a mile wide. The Fondalen snow- 
 field, in latitude <)(>° or fi7°. is of nearly the same size with 
 
 " .\ir:rricaii .Journal of Science," vol. cxxxii, 1886, p. 77. 
 
GLACIERS IN OTHER PARTS OF THE WORLD. 107 
 
 the preceding, and from it glaciers descend to the ocean-level. 
 The Folgefon snow-field, still farther north, occupies an area 
 of about one hundred square miles, from which three glaciers 
 of about the same rank as the preceding descend to the sea. 
 
 To the north of the Scandinavian Peninsula the islands of 
 Spitzbergen, Nova Zembla, and Franz-Josef Land, all lying 
 above latitude 70°, and the latter north of latitude 80°, are 
 deeply covered with glacial ice in their higher portions. 
 Speaking of Magdalena Bay in Spitzbergen, Dr. G. Hartwig 
 writes : 
 
 Foiir glaciers reach down this noble inlet • one, called the 
 Wagon- Way, is 7,000 feet across at its terminal cliff, which is 
 300 feet high, presenting a magniiicent wall of ice. But the 
 whole scene is constructed on so colossal a scale that it is only 
 on a near approach that the glaciers appear in all their impos- 
 ing grandeur. . . . Besides the glaciers on Magdalena Bay, 
 Spitzbergen has many others that protrude their crystal walls 
 down to the water's edge ; and yet but few icebergs, and the 
 largest not to be compared with the productions of Baffin 
 Bay, are drifted from the shores of Spitzbergen into the open 
 sea. The reason is that the glaciers usually terminate where 
 the sea is shallow, so that no very large mass if dislodged can 
 float away, and they are at the same time so frequently dismem- 
 bered by heavy swells that they can not attain any great size.* 
 
 The edge of the coast of the island of Franz-Josef Land 
 is quite generally formed by the precipitous ends of glaciers 
 a hundred feet or more in height and of unknown depth. 
 
 Iceland, too, has its glaciers in its more elevated portions, 
 though nowhere do they come down to the sea-level. The 
 snow-field of Yatna Jokull, with an extreme elevation of 
 6,000 feet, has an area of 3,000 square miles. From recent 
 reports it would seem that the glaciers of Iceland have for 
 some time been rapidly advancing. 
 
 In Asia glaciers are found to a limited extent in the 
 Caucasus Mountains, especially near the central portion of 
 
 * " Polar World," pp. 135, 136. 
 
108 THE ICE AGE IN NORTH AMERICA. 
 
 the range, where for a distance of 120 miles the average 
 height is 12,000 feet, while several individual peaks rise 
 higher than 16,000 feet. The snow-line in this range is from 
 11,000 to 12,000 feet above the sea-level, and in no case do 
 the glaciers descend much lower than the 6,000-foot level. 
 The Ural Mountains — owing probably to their being so nar- 
 row as not to afford space for large snow-fields — are entirely 
 without glaciers. In Central Asia, however, where peaks in 
 many cases rise upwards of 20,000 feet, glaciers appear on a 
 grand scale in the Hindu Kush, the Tian Shan and the Altai 
 mountains and in those surrounding the Pamir. While 
 in the Himalayan range, about the head of the Indus, glaciers 
 of great size are reported. That at the head of the Basha 
 River "is over thirty miles in length, its lower part, for a 
 distance of twenty or twenty-five miles, being about a 
 mile and a half in width; above this — for some distance 
 at least — it is still vnder, a marked feature being its small 
 inclination; along a large portion of its course it has an angle 
 of slope of not over one and a half or two degrees. 
 
 " At the head of the Braldu Valley, an easterly tributary 
 of the Shigar, is one of the largest known glaciers — that of 
 Baltoro. This is said by the officers of the survey to be 
 thirty-five miles in length, ' measured along a central line from 
 its termination up to peak K*.' The Biafo Glacier, the foot 
 of which is about ten miles vest of the Baltoro, is said to be 
 over forty miles long." * 
 
 At the heads of the Sutlej and the Ganges similar glacial 
 developments are witnessed, as well as at various other points 
 throughout the whole length of the range. 
 
 Passing to South America, we find, according to the best 
 reports, that until reaching the southern border of Chili gla- 
 ciers are infrequent and relatively small. According to Mr. 
 Whymper, no glaciers in Equador descend as low as 12,000 
 feet above the sea, and the glaciers in that region are largest 
 on the eastern side. Only on Cotopaxi, Chimborazo, and Illin- 
 
 * Whitney's " Climatic Changes," pp. 284, 285. 
 
GLACIERS IS OTHER PARTS OF THE WORLD. 109 
 
 issa are tlie glaciers comparable to those on Mont Blanc. 
 In Chili, in the province of Colchagua, about latitude 35°, 
 glaciers begin to appear, descending somewhat below the 
 6,000-foot level. " Proceeding southward from Colchagua, we 
 pass into a region in which the climatic conditions are very 
 different from those prevailing in the country farther north. 
 The ranges border the sea very closely, the amount of pre- 
 cipitation increasing and becoming more generally distributed 
 throughout the year. The temperature, at the same time di- 
 minishes, and all the conditions favorable to the formation of 
 glaciers are found to prevail. In consequence of this, there is 
 an extensive display of snow and ice along the southern coast 
 of Chili, and especially at the very extremity of the conti- 
 nent." 
 
 "In Tierra del Fuego," writes Mr. Darwin, "the snow- 
 line descends very low, and the mountain sides are abrupt ; 
 therefore we might expect to iind glaciers extending far 
 down their Hants. Nevertheless, when on first beholding, in 
 the middle of summer, many of the creeks on the northern 
 side of the Beagle channel tenninated by bold precipices of 
 ice overhanging the salt water, I felt greatly astonished ; for 
 the mountains from which they descended were far from 
 being very lofty." * 
 
 Darwin's observations upon the glaciers of South America 
 are still standard, and are worthy of fuller reproduction. In 
 his " Voyage of the Beagle " he says : 
 
 The descent of glaciers to the sea must, I conceive, mainly 
 depend (subject, of course, to a proper supply of snow in the 
 upper region) on the lowness of the line of perpetual snow on 
 steep mountains near the coast. . As the snow-line is so low in 
 Tierra del Fuego, we might have expecbed that many of tbe 
 glaciers would have reached the sea. Nevertheless, I was as- 
 tonished when I first saw a range, only from 3,000 to 4,000 
 feet in height, in the latitude of Cumberland, with every val- 
 ley filled with streams of ice descending to the sea-coast. 
 
 * Whitney's " Climatic Changes," pp. 272, 273. 
 
no THE ICE AOE IX NORTH AMERICA. 
 
 Almost every arm of the sea whieh penetrates to the interior 
 higher chain, not only in Tierra del Fuego, but also on the 
 coast for 650 miles northward, is terminated by "tremendous 
 and astonishing glaciers," as described by one of the officers 
 on the survey. Great masses of ice frequently fall from these 
 icy cliffs, and the crash reverberates, like the broadside of a 
 man-of-war, through the lonely channels. These falls pro- 
 duce great waves, which break on the adjoining coasts. It is 
 known that earthquakes frequently cause masses of earth to 
 fall from sea-cliffs : how terrific, then, would be the effect of 
 a severe shock (and such occur here) on a body like a glacier, 
 already in motion, and traversed by fissures ! I can readily 
 believe that the water would be fairly beaten back out of the 
 deepest channel, and then, returning with an overwhelming 
 force, would whirl about huge masses of rock like so much 
 chaff. In Eyre's Sound, in the latitude of Paris, there are 
 immense glaciers, and yet the loftiest neighboring mountain is 
 only 6,200 feet high. In this sound about fifty icebergs were 
 seen at one time floating outward, and one of them must have 
 been at least 168 feet in total height. Some of the icebergs 
 were loaded with blocks of no inconsiderable size, of granite 
 and other rocks, different from the clay-slate of the surround- 
 ing mountains. The glacier farthest from the pole, surveyed 
 during the voyages of the Adventure and Beagle, is in latitude 
 46° 50', in the Gulf of Penas. It is fifteen miles long, and in 
 one part seven broad, and descends to the sea-coast. But even 
 a few miles northward of this glacier, in the Laguna de San 
 Rafael, some Spanish missionaries encountered "many ice- 
 bergs, some great, some small, and others middle-sized," in a 
 narrow arm of the sea, on the 22d of the month correspond- 
 ing with our June, and in a latitude corresponding with that 
 of the Lake of Geneva ! 
 
 In Europe, the most southern glacier which comes down to 
 the sea is met with, according to Von Buch, on the coast of 
 Noi'way, in latitude 67". Now, this is more than 20° of lati- 
 tude, or 1,230 miles, nearer the pole than the Laguna de San 
 Rafael. The position of the glaciers at this place and in the 
 Gulf of Penas may be put even in a more striking point of 
 view, for they descend to the sea-coast, within 7J° of latitude. 
 
GLACIERS m OTHER PARTS OF THE WORLD, m 
 
 or 450 miles, of a harbor, where three species of oliva, a voluta, 
 and a terebra are the commonest shells, within less than 9° 
 from where palms grow, within 4^° of a region where tlie 
 jaguar and puma range over the plains, less than 3J° from 
 arborescent grasses, and (looking to the westward in the same 
 hemisphere) less than 3° from orchidaceous parasites, and 
 within a single degree of tree-ferns ! * 
 
 ]\Ir. Darwin's experience was so similar to that of those 
 who visit Alaska (see Chapter III, page 50), that another 
 extract will prove especially instructive by way of compari- 
 son. Speaking of the Straits of Magellan, he says : 
 
 The lofty mountains on the north side compose the granitic 
 axis, or backbone of the country, and boldly rise to a height 
 of between 3,000 and 4,000 feet, with one peak above 6,000 
 feet. They are covered by a wide mantle of perpetual snow, 
 and numerous c^cades pour their waters, through the woods, 
 into the narrow channel below. In many parts, magnificent 
 glaciers extend from the mountain-side to the water's edge. 
 It is scarcely possible to imagine anything more beautiful than 
 the beryl-like blue of these glaciers, and especially as contrasted 
 with the dead white of the upper expanse of snow. The frag- 
 ments which had fallen from the glacier into the water were 
 floating away, and the channel, with its icebergs, presented for 
 the space of a mile a miniature likeness of the Polar Sea. The 
 boats being hauled on shore at our dinner-hour, we were ad- 
 miring from the distance of half a mile a perpendicular cliff 
 of ice, and were wishing that some more fragments would fall. 
 At last down came a mass with a roaring noise, and imme- 
 diately we saw the smooth outline of a wave traveling toward 
 us. The men ran down as quickly as they could to the boats ; 
 for the chance of their being dashed to pieces was evident. 
 One of the seamen just caught hold of the bows as the curling 
 breaker reached it. He was knocked over and over, but not 
 hurt ; and the boats, though thrice lifted on high and let fall 
 again, received no damage. This was most fortunate for us, 
 for we were a hundred miles distant from the ship, and we 
 
 ■ " Voyage of the Beagle," edition of 18'(2, pp. 245-247. 
 
112 THE ICE AGE IN NORTH AMERICA. 
 
 should have been left without proyisions or fire-arms. I had 
 previously observed that some large fragments of rock on the 
 beach had been lately displaced, but, until seeing this wave, 
 I did not understand the cause. One side of the creek was 
 formed by a spur of mica-slate ; the head by a cliff of ice about 
 forty feet high ; and the other side by a promontory fifty feet 
 high, built up of huge rounded fragments of granite and mica- 
 slate, out of which old trees were growing. This promontory 
 was evidently a moraine, heaped up at a period when the gla- 
 cier had greater dimensions.* 
 
 Of the glaciers of New Zealand the following succinct 
 account of Whitney must suflBce : 
 
 On the western coast of the southern island, between the 
 parallels of 42° and 45°, rises abruptly from the sea a grand 
 range of mountains, the culminating point of which, Mount 
 Cook, is about 13,000 feet in elevation. Along this chain, for 
 a length of about one hundi-ed miles, are developed numerous 
 groups of glaciers, some of which are not much inferior in size 
 to the largest of those of the Alps. The Tasman Glacier is 
 said by Haast, who first scientifically explored and described 
 these mountains, to be ten miles in length and a mile and 
 three quarters broad at its termination, the lower portion, for 
 a distance of three miles, being covered with morainic de- 
 tritus, f 
 
 Glacial conditions prevail over the Antarctic Continent. 
 Icebergs of great size are frequently encountered up to 58° 
 south latitude, in the direction of Cape Horn, and as far as 
 latitude 33° in the direction of Cape of Grood Hope. Tlie 
 number and size of these, of which more particulars will be 
 given presently, are such as to necessitate an extensive area 
 of glaciers about the south pole. Much of all that is known 
 of the Antarctic Continent was discovered by Sir J. C. 
 Hoss during the period extending from 1839 to 1843, when, 
 between the parallels of 70° and 78° south latitude, he en- 
 
 * " VoyaRe of the Beagle," edition of 18'?2, pp. 224, 225. 
 + " Climatic Changes," pp. 273, 2H. 
 
0LAGIER8 IN OTHER PARTS OF TEE WORLD. 113 
 
 countered in his explorations a precipitous mountain-coast, 
 rising from 7,000 to 10,000 feet above tide. Through the 
 valleys intervening between the mountain-ranges huge gla- 
 ciers descended, and " projected in many places several miles 
 into the sea, and terminated in lofty perpendicular cliffs. 
 In a few places the rocks broke through their icy covering, 
 by which alone we could be assured that land formed the 
 nucleus of this, to appearance, enormous iceberg." * 
 
 Again, speaking of the region in the vicinity of the lofty 
 volcanoes Terror and Erebus, between 10,000 and 12,000 feet 
 high, the same navigator says : 
 
 " We perceived a low white line extending from its extreme 
 eastern point as far as the eye could discern to the eastward. 
 It presented an extraordinary appearance, gradually increasing 
 in height as we got nearer to it, and proving at length to be a 
 perpendicular cliff of ice, between 150 and 300 feet above the 
 level of the sea, perfectly flat and level at the top, and with- 
 out any fissures or promontories on its even seaward face. 
 What was beyond it we could not imagine ; for, being much • 
 higher than our mast-head, we could not see anything except 
 the summit of a lofty range of mountains extending to the 
 southward as far as the seventy-ninth degree of latitude. 
 These mountains, being the southernmost land hitherto die- 
 covered, I felt great satisfaction in naming after Sir Edward 
 Parry. . . . Whether Parry Mountains again take an easterly 
 trending and form the base to which this extraordinary mass 
 of ice is attached, must be left for future navigators to deter- 
 mine. If there be land to the southward, it must be very 
 remote, or of much less elevation than any other part of the 
 coast we have seen, or it would have appeared above the bar- 
 rier." 
 
 This ice-cliff or barrier was followed by Captain Ross as far 
 as 198° west longitude, and found to preserve very much the 
 same character during the whole of that distance. On the 
 lithographic view of this great ice-sheet given in Eoss's work 
 it is described as "part of the South Polar Barrier, to 180 
 
 * Quoted by Whitney in "Climatic Changes," p. 314. 
 
114 THE ICE AGE IN NORTH AMERICA. 
 
 feet above the sea-level, 1,000 feet thick, and 450 miles in 
 length." 
 
 A similar vertical wall of ice was seen by D'Urville, off the 
 coast of Adelie Land. He thus describes it : " Its appearance 
 was astonishing. We perceived a cliff having a uniform eleva- 
 tion of from 100 to 150 feet, forming a long line extending off 
 to the west. . . . Thus for more than twelve hours we had 
 followed this wall of ice, and found its sides everywhere per- 
 fectly vertical and its summit horizontal. Not the smallest 
 irregularity, not the most inconsiderable elevation, broke its 
 uniformity, for the twenty leagues of distance which we fol- 
 lowed it during the day, although we passed it occasionally at 
 a distance of only two or three miles, so that we could make 
 out with ease its smallest irregularities. Some large pieces of 
 ice were lying along the side of this frozen coast ; but, on the 
 whole, there was open sea in the offing." * 
 
 In addition to the recent direct observations upon the 
 glaciers of the Antarctic Continent, we are permitted to 
 turn to an important source of indirect evidence furnished 
 by the icebergs encountered in the region. Many of these 
 are of such size as to indicate an enormous depth to the glacial 
 ice of which they are fragments, and imply the existence of 
 a glaciated area larger even than Greenland. In reading the 
 accounts of icebergs we should bear in mind that the specific 
 gravity of ice is such that where there is one cubic foot of 
 au iceberg above the water's surface there are seven or eight 
 cubic feet below the surface : so that, if the form of the berg 
 could be supposed to be symmetrical, we should multiply 
 the height of the berg above water by eight or nine to get 
 its perpendicular dimension. But as the forms of the ice- 
 bergs are usually irregular, this rule can not always be ap- 
 plied. In several of the instances to be referred to, however, 
 the masses are so large, and the forms so regular, that we 
 can not be far amiss in applying the rule. Some of these 
 masses of floating ice are of almost incredible size, and their 
 
 ■ Quoted by Whitney in "Climatic Changes," ' pp. 318, 316. 
 
GLACIERS IS OTHER PARTS OF THE WORLD. 115 
 
 origin can only have been upon large surfaces of land in 
 every way favorably situated for the accumulation of snow 
 and the formation of glaciers. The following are a few of 
 the examples reported a century ago by Captain Cook : 
 
 At eight o'clock saw an island of ice to the westward 
 of us, being then in the latitude of 50° 40' south, and longi- 
 tude 2° 0' east of the Cape of Good Hope. Soon after, the 
 wind moderated, and we let all the reefs out of the top-sails, 
 got the sprit-sail -yard out, and top-gallant-mast up. The 
 weather coming hazy, I called the Adventure by signal under 
 my stern ; which was no sooner done, than the haze increased 
 so much, with snow and sleet, that we did not see an island of 
 ice, which we were steering directly for, till we were less than 
 a mile from it. I judged it to be about fifty feet high, and 
 half a mile in circuit. It was flat at the top, and its sides rose 
 in a perpendicular direction, against which the sea broke ex- 
 ceedingly high. . . . 
 
 At one o'clock we steered for an island of ice, thinking, if 
 there were any loose ice round it, to take some on board, and 
 convert it into fresh water. At four we brought to, close un- 
 der the lee of the island ; where we did not find what we 
 wanted, but saw upon it eighty-six penguins. This piece of 
 ice was about half a mile in circuit and one hundred feet high 
 and upward, for we lay for some minutes with every sail be- 
 calmed under it. . . . 
 
 At nine in the morning we bore down to an island of ice 
 which we reached by noon. It was full half a mile in circuit, 
 and two hundred feet high at least, though very little loose ice 
 about it. But while we were considering whether or not we 
 should hoist out our boats to take some up, a gi'eat quantity 
 broke from the island. Upon this we hoisted out our boats, 
 and went to work to get some on board. The pieces of ice, 
 both great and small, which broke from the island, I observed, 
 drifted fast to the westward ; that is, they left the island in 
 that direction, and were, in a few hours, spread over a large 
 space of sea. . . . 
 
 Finding here a good quantity of loose ice, I ordered two 
 boats out, and sent them to take some on board. While this 
 
116 
 
 THE ICE AGE IN yOETH AMERICA. 
 
 was doing, the island, which was not less than half a mile in 
 circuit, and three or four hundred feet high above the surface 
 
 of the sea, turned nearly bottom up. Its height, by this 
 circumstance, was neither increased nor diminished ajipar- 
 ently. . . . 
 
 In the evening we had three islands of ice in sight, all of 
 them large ; especially one, which was larger than any we had 
 yet seen. The side opposed to us seemed to be a mile in ex- 
 tent ; if so, it could not be less tlian three in circuit. As we 
 passed it in the night, a continual cracking was heard, occa- 
 sioned, no doubt, by pieces breaking from it. For, on the 
 morning of the 6th, the sea, for some distance round it, was 
 covered with large and small pieces : and the island itself did 
 not appear so large as it had done the evening before. It 
 could not be less than one hundred feet high ; yet such was 
 the impetuous force and height of the waves which were 
 broken agaiiist it, by meeting with such a sudden resistance, 
 that they rose consideraljlv higher.* 
 
 For a series of years the Boai'd of Trade in Eng'land col- 
 lected statistics from the navigators of the Southern Ocean 
 who rejDorted icebergs eucoimtered in their voyages. From 
 
 ' Voyiifje ruund the Woild," pp. 20, 29, 48-00, 54. 
 
GLACIERS IN OTHER PARTS OF THE WORLD. 117 
 
 these reports, and from a paper of Mr. Towson upon the 
 subject, published by the Board of Trade, Mr. Croll makes 
 the following collection of facts concerning them, premising 
 that, " with one or two exceptions, the heights of the bergs 
 were accurately determined by angular measurement " : 
 
 September 10, 1856.— The Lightning when in latitude 55° 
 33' south, longitude 140° west, met with an iceberg 430 feet 
 high. 
 
 November, 1839.— In latitude 41° south, longitude 87° 30' 
 east, numerous icebergs 400 feet high were met with. 
 
 September, 1840.— In latitude 37° south, longitude 15° 
 east, an iceberg 1,000 feet long and 400 feet high was met 
 with. 
 
 February, 1860. — Captain Clark, of the Lightning, when 
 in latitude 55° 20' south, longitude 132° 45' west, found an 
 iceberg 500 feet high and three miles long. 
 
 December 1, 1859. — An iceberg, 580 feet high, aud from 
 two and a half to three miles long, was seen by Captain Smith- 
 ers, of the Edmond, in latitude 50° 53' south, longitude 43° 58' 
 west. So strongly did this iceberg resemble land that Captain 
 Smithers belicTed it to be an island, and reported it as such, 
 but there is little or no doubt that it was in reality an iceberg. 
 There were pieces of drift-ice under its lee. 
 
 November, 1856. — Three large icebergs, 500 feet high, 
 were found in latitude 41° 0' south, longitude 42° 0' east. 
 
 January, 1861. — Five icebergs, one 500 feet high, were met 
 with in latitude 55° 46' south, longitude 155° 56' west. 
 
 January, 1861.— In latitude 56° 10' south, longitude 160° 
 0' west, an iceberg 500 feet high and half a mile long was 
 found. 
 
 January, 1867. — The bark Scout, from the west coast of 
 America, on her way to Liverpool, passed some icebergs 600 feet 
 in height and of great length. 
 
 April, 1864. — The Eoyal Standard came In collision with 
 an iceberg 600 feet in height. 
 
 December, 1856. — Four large icebergs, one of them 700 
 feet high, and another 500 feet, were met with in latitude 50° 
 14' south, longitude 42° 54' east. 
 
118 THE ICE AGE IN NORTH AMERICA. 
 
 December 25, 1861. — The Queen of Nations fell in with an 
 iceberg in latitude 53° 45' south, longitude 170° 0' west, 720 
 feet high. 
 
 December, 1856. — Captain P. Wakem, ship Ellen Radford, 
 found, in latitude 52° 31' south, longitude 43° 43' west, two 
 large icebergs, one at least 800 feet high. 
 
 Mr. Towson states that one of our most celebrated and 
 talented naval surveyors informed him that he had seen ice- 
 bergs in the southern regions 800 feet high. 
 
 March 23, 1855. — The Agneta passed an iceberg in latitude 
 53° 14' south, longitude 14° 41' east, 960 feet in height. 
 
 August 16, 1840. — The Dutch ship. General Baron von 
 Geen, passed an iceberg 1,000 feet high in latitude 37° 32' south, 
 longitude 14"^ 10' east. 
 
 May 15, 1859.— The Roseworth found, in latitude 53° 40' 
 south, longitude 123° 17' west, an iceberg as large as " Tristan 
 d'Acunha."* 
 
 Upon these facts Mr, CroU remarks : 
 
 In the regions where most of these icebergs were met with, 
 the mean density of the sea is about 1 •0256. The density of 
 ice is '92. The density of icebergs to that of the sea is there- 
 fore as 1 to 1'115 ; consequently, every foot of ice above water 
 indicates 8 '7 feet below water. It therefore follows that those 
 icebergs 400 feet high had 3,480 feet under water — 3,880 feet 
 would consequently be the total thickness of the ice. The 
 icebergs which were 500 feet high would be 4,850 feet thick, 
 those 600 feet high would have a total thickness of 5,820 feet, 
 and those 700 feet high would be no less than 6,7^90 feet thick, 
 which is more than a mile and a quarter. The iceberg 960 
 feet high, sighted by the Agneta, would be actually 9,312 feet 
 thick, which is upward of a mile and three quarters. 
 
 Although the mass of an iceberg below water compared to 
 that above may be taken to be about 8 "7 to 1, yet it would not 
 be always safe to conclude that the thickness of the ice be- 
 low water bears the same proportion to its height above. If 
 the berg, for example, be much broader at its base than at its 
 
 * " Climate and Time," pp. 382-385. 
 
GLAClEIiS IN OTHER FART6 OF THE WORLL. 119 
 
 top, the thickness of the ice below water would bear a less pro- 
 portion to the height above water than as 8-7 to 1. But a berg, 
 such as that recorded by Captain Clark, 500 feet high and three 
 miles long, must have had only 1 to 8-7 of its total thickness 
 
 Fin. 39. — Floatint: lierir. f^hnwintr tho proportions ahove and under ttir wiirer 
 
 above water. The same remark applies also to the one seen by 
 Captain Smithers, which was 580 feet high, and so large that it 
 was taken for an island. This berg must have been 5,628 feet 
 in thickness. The enormous berg which came in collision with 
 the Royal Standard must have been 5,820 feet thick. It is not 
 stated what length the icebergs 730, 960, and 1,000 feet high 
 respectively were ; but supposing that we make considerable 
 allowance for the possibility that the proportionate thickness 
 of ice below water to that above may have been less tjian as 8'7 
 to 1, still we can hardly avoid the conclusion that the icebergs 
 were considerably above a mile in thickness. But if there are 
 icebergs above a mile in thickness, then there must be land-ice 
 somewhere on the southern hemis])here of that thickness. In 
 short, the great antarctic ice-cap must in some places be over a 
 mile in thickness at its edge. 
 
120 THE ICE AGE IX NORTH AMERICA. 
 
 Interest in Antarctic exploration did not revive until the 
 beginning of the present century, but since then it has been 
 very active. In 1901 Captain Scott of the English navy set 
 out in the vessel Discovery and, during the following year, 
 reached a point within 670 miles of the south pole, 100 miles 
 nearer than anyone had been before. 
 
 On August 7, 1907, Lieut. Ernest Shackelton, of the Eng- 
 hsh navy sailed from Plymouth for the purpose of reaching 
 the south pole. On January 6, 1909, his party reached a 
 point within ninety-three geographical miles of the pole and 
 then was compelled to turn back. Here they were on a plateau 
 between 10,000 and 11,000 feet above sea-level, which seemed 
 to stretch imbroken southward as far as their glass could 
 extend their vision, thus revealing conditions very different 
 from those about the north pole, where there is a sea several 
 thousand feet deep covered with drifting ice. 
 
 According to Lieutenant Shackelton, "We now know that 
 the Great Southern Ice Barrier is bounded by mountains 
 running in a southeasterly direction from 78° south at least, 
 and that an immense glacier leads to a plateau over 10,000 
 feet above the sea level, on which is situated the geographical 
 south pole. 
 
 "Numerous inland mountains have been discovered, and 
 specimens of rock from them show that at some period in 
 the geological history of the earth a warm climate prevailed 
 in these ice bound regions." 
 
 "The discovery of microscopical life in the frozen lakes is 
 extremely iateresting. The scientists of the expedition demon- 
 strated that the tiny rotifers could exist in a temperature of 
 100° of frost, and also emerge imscathed from the test of a 
 
 temperature of 200°F Strange as it may seem, 
 
 there is a large marine fauna in the icy waters of the Antarctic. 
 The temperature of the sea in those regions varies but little 
 in winter and summer, and this fact is conducive to an abun- 
 dant marine life." 
 
GLACIERS IN OTHER PARTS OF THE WORLD 121 
 
 Among the most important discoveries was that of the 
 South Magnetic Pole. Leaving their winter quarters on Octo- 
 ber 5th, they traveled westward amid great difficulties and 
 dangers 250 miles along the coast on the sea ice, "relaying" 
 the whole distance. As the summer advanced they began to 
 suffer from the heat, and although they were traveling over 
 ice they often had to divest themselves of their outer gar- 
 ments. On the 16th of December they left the shore and 
 struck inland in the direction of the Magnetic Pole, which 
 they estimated to be about 200 niles distant. During this 
 journey they encountered, though in the midst of summer, a 
 heavy snowfall and a succession of blizzards extending 
 through a fortnight. They also, like the southern party 
 had to ascend a high plateau and found the ice covering to 
 be a perfect maze of crevasses, which rendered travel almost 
 impossible. Following the magnetic meridian, and ascend- 
 ing a succession of terraces, they at length reached an undulat- 
 ing snow plain 7,000 or 8,000 feet above sea-level, where the 
 traveling was easier, and on the 16th of January reached the 
 object of their search in latitude 72° 45' south, longitude 
 145.° Here they hoisted the Union Jack and claimed the 
 land in the name of his Majesty the King of England. The 
 cold at this elevation was intense, and there was a continual 
 ice wind from the southwest, with a succession of blizzards. 
 Hoisting a sail and thus taking advantage of this wind the 
 party reached their depot on the 3d of February in a state of 
 semi-starvation. 
 
CHAPTEK VI. 
 
 SIGNS OF FORMER GLAOIATION. 
 
 Before attempting to delineate the exact southern 
 boundary of the ice during the height of the Glacial period 
 in North America, it will be necessary briefly to discuss the 
 evidence upon which the inferences concerning the Glacial 
 period are based. The reader will ask : How is it possible 
 to determine, with any reasonable degree of accuracy, the 
 sxtent of the region formerly covered by glacial ice, but 
 Kfhich has been free from such covering for many thousand 
 years, and during all that time has been subjected to the 
 disintegrating and modifying influences connected with the 
 ceaseless operation of the ordinary forces of Nature ? 
 
 The consideration of this question will introduce us not 
 only to some of the most interesting problems of this par- 
 ticular subject, but to some of the fundamental principles 
 underlying all inductive reasoning. The study of the great 
 Ice age, like all other branches of geology, deals with the 
 effects of past causes. From the marks which have been 
 left upon the surface of the earth, we endeavor by scientific 
 processes to reproduce to our imagination the condition of 
 things which would accoimt for these marks. As reasonable 
 beings, we are compelled to bring into the field of thought 
 a past cause sufficient to produce all the results observed, 
 both positive and negative ; and when our imagination has 
 found an adequate cause, true science compels us to rest with 
 that. 
 
 From observation upon living glaciers, and from the 
 known nature of ice, we may learn to recognize the track 
 
SIGXS OF FORMER GLAVIATION. 
 
 123 
 
 of a glacier as readily and unmistakably as we would the 
 familiar foot-prints of an animal. The indications npon which 
 glacialists have depended for their information as to the ex- 
 tent of the glaciated region during the great Ice age are of 
 three kinds : 1. Grooves and scratches preserved upon the 
 rocks in place and upon the bowlders and })ebbles shoved 
 along under the ice. 2. The extensive unstratitied deposits 
 called " till," which are traceable to glacial action. 3. Trans- 
 ported material found in such positions tliat it must have 
 been left by glacial ice rather than Hoating ice. 
 
 In respect of the nature of ice we are compelled to ad- 
 mit that it is capable of motion like such semi-flnids as eool- 
 
 FiG 40 —Scratched stone from tlic till of Boston. Katural size ahont one foot and a hall 
 long l>y ten inches wide. (From photograph.) 
 
 ino- pitch or lava. But, though it does move, it is not capa- 
 ble of adapting itself so perfectly as a real fluid to the 
 
SIGNS OF FORMER OLAOFATION. 125 
 
 inequalities of the country. From this comparatively solid 
 character of ice certain important results must follow. It 
 is easy to see that the stones of all sizes, while being dragged 
 along underneath the ice, would be held in a comparatively 
 firm grasp so as to be polished and striated and scratched in 
 a peculiar manner. On the shores of bays and lakes and in 
 bottoms of streams we find that the stones are polished and 
 I'ounded in a symmetrical manner, but are never scratched. 
 The mobility of water is such that the edges and comers of 
 the stones are rubbed together by a force acting successively 
 in every possible direction. But in and under the ice the 
 firm grasp of the stiff semi-fluid causes the stony fragments 
 to move in a nearly uniform direction, so that they grate 
 over the underlying rocks like a rasp, wearing down the 
 rocks beneath and slowly grinding them to powder, and, 
 at the same time, being worn themselves in the process. 
 Fi'om the stability of the motion of such a substance as ice 
 there would, from the nature of the case, result groovings 
 and striation both on the rocks beneath and on the bowlders 
 and pebbles which, like iron plowshares, are forced over 
 them. Scratched surfaces of rock and scratched stones are 
 therefore, in ordinary eases, most trustworthy indications of 
 glacial action. The direction of the scratches upon these 
 glaciated bowlders and pebbles is, also, worthy of notice. 
 The scratches upon the loose pebbles are mainly in the direc- 
 tion of their longest diameter — a result which follows from 
 a mechanical principle, that bodies forced to move through 
 a resisting medium must swing around so as to proceed in 
 the line of least resistance. Hence the longest diameter of 
 such moving bodies will tend to come in line with the direc- 
 tion of the motion. 
 
 A scratched surface is, however, not an infallible proof 
 of the former presence of a glacier where such a surface is 
 found, or, indeed, of glacial action at all. A stone scratched 
 by glacial forces may float away upon an iceberg, and be 
 deposited at a great distance from its home. Indeed, ice- 
 bergs and shore-ice may produce, in limited degree, the phe- 
 
126 THE ICE AGE IJf SOJiTE AMERICA. 
 
 noinena of striation which we have just described. One can 
 but admire the enthusiasm with which the old defenders of 
 the iceberg theory dwelt upon the capacity of icebergs and 
 shore-ice to polish, groove, and scratch the surfaces over 
 wbieh they moved. Sir Charles Lyell tells us, in the ac- 
 count of his first visit to America, how he stood at the foot 
 of a cliff at Cape Blomidon, Nova Scotia, transfixed at the 
 sight of recent furrows which were the exact counterpart of 
 the grooves of ancient date which he had elsewhere described. 
 So extensive were these, that they seemed for the moment 
 to render the glacial theory' unnecessary : 
 
 As I was strolling along the beach at the base of these ba- 
 saltic cliffs, collecting minerals, and occasionally recent shells 
 at low tide, I stopped short at the sight of an unexpected phe- 
 nomenon. The solitary inhabitant of a desert island could 
 scarcely have been more startled by a hunian foot-print in the 
 sand, than I was on beholding some recent furrows on a ledge 
 of sandstone under my feet, the exact counterpart of those 
 grooves of ancient date which I have so often described in this 
 work, and attributed to glacial action. After having searched 
 in vain at Quebec for such indications of a modern date, I had 
 despaired of witnessing any in this part of the world. I was 
 now satisfied that, whatever might be their origin, those before 
 me were quite recent. 
 
 The inferior beds of soft sandstone which are exposed at 
 low water at the base of the cliff at Cape Blomidon, form a 
 broad ledge of bare rock, to the surface of which no sea-weed 
 or barnacles can attach themselves, as the stone is always wear- 
 ing away slowly by the continual passage of sand and gravel, 
 washed over it from the talus of fallen fragments which lies at 
 the foot of the cliff on the beach above. The slow but con- 
 stant undermining of the perpendicular cliff forming this 
 promontory, round which the powerful currents caused by the 
 tide sweep backward and forward with prodigious velocity, 
 must satisfy every geologist that the denudation by which the 
 ledge in question has been exposed to view is of modern date. 
 Whether the rocks forming the cliff extended so far as the 
 water's edge, ten, fifty, or one hundred years ago, I hare no 
 
SIGSS OF FORMER OLACIATION. 127 
 
 means of estimating ; but the exact date and rate of destruc- 
 tion are immaterial. On this recently-formed ledge I saw sev- 
 eral straight furrows half an inch broad, some of them very 
 nearly parallel, others diverging, the direction of the former 
 being north 35° east, or corresponding to that of the shore at 
 this point. After walking about a quarter of a mile, I found 
 another set of similar furrows, having the same general direc- 
 tion within five degrees ; and I made up my mind that, if these 
 grooves could not be referred to the modern instrumentality of 
 ice, it would throw no small doubt on the glacial hypothesis. 
 When I asked my guide— a peasant of the neighborhood — 
 whether he had evfer seen much ice on the spot where we stood, 
 the heat was so excessive (for we were in the latitude of the 
 south of France, 45° north), that I seemed to be putting a 
 strange question. He replied that, in the preceding winter of 
 1841, he had seen the ice, in spite of the tide, which ran at the 
 rate of ten miles an hour, extending in one uninterrupted mass 
 from the shore where we stood to the opposite coast at Parrs- 
 borough, and that the icy blocks, heaped od each other, and 
 frozen together or "packed" at the foot of Cape Blomidon, 
 were often fifteen feet thick, and were pushed along, when the 
 tide rose, over the sandstone ledges. He also stated that frag- 
 ments of the "black stone " which fell from the summit of the 
 cliff, a pile of which lay at its base, were often frozen into the 
 ice, and moved along with it. I then examined these fallen 
 blocks of amygdaloid scattered around me, and observed in 
 them numerous geodes coated with quartz-crystals. I have 
 no doubt that the hardness of these gravers, firmly fixed in 
 masses of ice, which, although only fifteen feet thick, are often 
 of considerable horizontal extent, have furnished suflBcient 
 pressure and mechanical power to groove the ledge of soft 
 sandstone. * 
 
 Stones are also striated by other agencies than moving ice. 
 Extensive avalanches and land-slides furnish conditions analo- 
 gous to those of a glacier, and might in limited and favor- 
 able localities simulate its results. In those larger geological 
 
 * " Travels in America," first series, vol. ii, pp, 144-146. 
 
SIGfjSrS OF FORMER QLACIATIOK. 129 
 
 movements, also, where the crust of the earth is broken and 
 the edges of successive strata are shoved over each other, a 
 species of striation is produced which in technical terms is 
 called a slickenside. Occasionally this deceives the inex- 
 perienced or incautious observer. But by due pains all these 
 semblances may be detected and eliminated from the prob- 
 lem, leaving a sufficient number of unquestionable phenom- 
 ena due to true glacial action. 
 
 A second indubitable mark of glacial action is found in 
 the character of the deposit left after the retreat of the ice. 
 Ice and water differ so much from each other in the extent of 
 their fluidity, that ordinarily there is little danger of confus- 
 ing the deposits made by thein. A simple water deposit is 
 inevitably stratiiied. The coarse and tine material can not be 
 deposited by water alone, simultaneously in the same place. 
 Along the shores of large bodies of water the deposits of 
 solid material are arranged in successive parallel lines, the 
 material growing finer and finer as the lines recede from the 
 shore. The force of the waves is such in shallow water that 
 they move pebbles of considerable size. Indeed, where the 
 waves strike against the shore itself, vast masses of rock are 
 oftentimes moved by the surf. But, as deeper water is 
 reached, the force of the waves becomes less and less at the 
 bottom, and so the transported material is correspondingly 
 fine, until, at the depth of about seventy feet, the force of 
 the waves is entirely lost ; and beyond that line nothing will 
 be deposited but fine mud, the particles of which are for- a 
 long while held in suspension before they settle. 
 
 In the deltas of rivers, also, the sifting power of water 
 may be observed. Where a mountain-stream first debouches 
 upon a plain, the force of its current is such as to move lai-ge 
 pebbles, or bowlders even, two or three feet in diameter. 
 But, as the current is checked, the particles moved by it be- 
 come smaller and smaller until in the head of the bay, or in 
 the broad current of the river which it enters, only the finest 
 sediment is transported. The difference between the size of 
 material transported by the same stream when in flood and 
 
130 THE ICE AGE IN NORTH AMERICA. 
 
 when at low water is very great, and is the main agent in pro- 
 ducing the familiar phenomena of stratification. During the 
 time of a flood vast bodies of pebbles, gravel, and sand are 
 pushed out by the torrent over the bead of the bay or delta 
 into which it pours ; while during the lower stages of water 
 only fine material is transported to the same distance ; and 
 this is deposited as a thin film over the previous coarse deposit. 
 Upon the repetition of the flood another layer of coarser 
 material is spread over the surface ; and so, in successive 
 stages, is built up in all the deltas of our great rivers a series 
 of stratified deposits. In ordinary circumstances it is impos- 
 sible that coarse and fine material should be intermingled in 
 a water deposit without stratification. Water moving with 
 various degrees of velocity is the most perfect sieve imagi- 
 nable ; so that a water deposit is of necessity stratified. 
 
 To this general principle, however, exception must be 
 made in the case of accumulations taking place slowly in 
 deep water containing icebergs from which bowlders and 
 pebbles may be dropped. These, of course, will be found 
 distributed through the tine deposit without stratification. 
 It is thought by President Chamberlin,* however, that in 
 cases where the bowlders dropped from the icebergs are of 
 marked irregularity in their configuration, their position in 
 the ooze at the bottom would betray their origin. Flattish 
 stones, in falling through the water, would often descend 
 edgewise, and would not uniformly lie in the mud upon 
 their flat surface. I have myself observed numerous places 
 in southern Ohio where the arrangement of the limestone 
 fragments abundantly illustrates and confirms this theory. 
 The horizontal position of such fragments in the clay of that 
 region seems to show that they were arranged in the deposit 
 by a moving ice-sheet, and were not dropped from floating ice. 
 
 It is evident that ice is so nearly a solid that the earthy 
 material deposited by it must be unassorted. The mud, sand, 
 gravel, pebbles, and bowlders, dragged along underneath a 
 
 * " Terminal Moraine of tiie Second Glacial Epoch," p. 297. 
 
132 THE IGE AGE IN NOBTH AMERICA. 
 
 moving stream of ice, must be left in an unstratified oondi- 
 tion — the coarse and the tine being indiscriminately mingled 
 together. If ow, this is the character of the extensive deposits 
 of loose material which cover what we designate as the gla- 
 ciated region. It is true that over this region there are extea- 
 sive stratified deposits. JBut these invariably mark the situa- 
 tion of abandoned lakes and water-courses. To these interest- 
 ing formations a special chapter will be devoted. But the 
 larger part of the region marked upon the map as glaciated 
 is covered with an unstratified deposit, in which are mingled 
 a variety of materials derived from rocks both of the locality 
 and of far-distant regions. Moreover, the pebbles in this de- 
 posit are the most of them polished and scratched after the 
 manner of those which we know to liave been subjected to 
 glacial action. Ordinarily there can be no question of the 
 glacial character of this formation, even when no considera- 
 tions are taken into account except those which appear in the 
 deposit itself. StiU, in certain situations, floating ice may 
 transport coarse material, and drop it in the midst of finer 
 silt, so as closely to simulate a true unstratified deposit. In 
 the majority of cases, however, the configuration of the coun- 
 try is such as to exclude the agency of floating ice from the 
 problem. 
 
 We come, therefore, in the third place, to a mass of 
 recently discovered facts which would seem to place the 
 glacial theory above all question. When once the limit of 
 these unstratified deposits, containing striated stones and 
 transported material, had been accurately determined, it was 
 found that the margin was exceedingly irregular in two re- 
 spects. The southern edge of this deposit is both sefrraU 
 and cremate — that is, it does not follow a straight east-and- 
 west line, but in places withdraws to the north, and in others 
 extends in lobe-shaped projections far to the south. This 
 constitutes its seiTate character. But it is the crenate char- 
 acter of its southern border which is of most significance. 
 The southern border, with its indentations and projections, 
 is not determined by any natural barrier. The southern 
 
SIGH'S OF FORMER GLACIATION. 133 
 
 boundary-line rises from the level of the sea at New Tork 
 to the height of the Blue Mountains in New Jersey, and 
 descends into the valley of the Delaware, and rises again 
 over the Blue Kidge in Pennsylvania, crossing the valley 
 between it and Pocono Mountain, where it runs for many 
 miles at an elevation of 2,000 feet above the sea, and descends 
 in a nearly straight line to the East Branch of the Susque- 
 hanna at Beach Haven, where it is not more than 500 feet 
 above the sea. Thence it continues onward in a diagonal 
 course across the AUeghanies, with their various subsidiary 
 valleys, to its great turning-point in southwestern New York. 
 Thence to the trough of the Mississippi, for a distance of 
 TOO or 800 miles, the line winds gradually down the west- 
 em flanks of the AUeghanies, paying little attention in its 
 deflections to the minor inequalities of the country. West 
 of the Mississippi the rise is equally gradual to northern 
 Dakota and Montana, where the glacial border is 2,000 or 
 3,000, and in British America 4,000, feet above the sea. 
 
 Thus it is not possible, by the supposition of any conceiv- 
 able submergence, to account for this line of demarkation. 
 Water which would have floated ice from the north to almost 
 any point along that line would have floated it farther south. 
 Consequently, the line must have been determined not by a 
 barrier which restrained a fluid, but by the irregular losses 
 of momentum such as would take place in a semi-fluid mov- 
 ing in the line of least resistance from various central points 
 of accumulation. 
 
 The reader will find the subject of this chapter treated 
 with great fullness by President Ohamberlin in the " Third 
 Annual Eeport of the United States Geological Survey," pp. 
 291-402, and in the " Seventh Report," pp. 149-248, where 
 the subject of rock-scoring is most fully illustrated. Numer- 
 ous illustrations in the present volume have been reserved for 
 the latter part of Chapter X, on " Glacial Erosion and Trans- 
 portation," which the reader will do well to consult in this 
 connection as well as in the order in which it occurs. 
 
CHAPTEE YII. 
 
 BOUNDARY OF THE GLACIATED AREA IN NORTH AMERICA, 
 
 Doubtless the Ice age both began and ended in a great 
 number of local glaciers which became confluent and con- 
 tinuous only during the middle of the period. One of the 
 most interesting evidences of the independent movement of 
 the different portions of the great North American ice-sheet 
 is to be found in the driftless region of southwestern Wis- 
 consin. Here is an area of several hundred square miles in 
 extent, occupying more or less of the adjoining area in Illi- 
 nois, Iowa, and Minnesota, which remained as an island in 
 the great continental expanse of ice. The ice moved past it 
 upon both sides, and then closed together upon the south, 
 and moved onward, a distance of about 300 miles, to the 
 vicinity of St. Louis. 
 
 When, in the year 1876, attention was first directed by 
 Mr. Clarence King,* Mr. Warren Upham,-|- and Professor 
 George H. Cook ^ to the terminal moraines of southern New 
 England and northern New Jersey, by President T. C. Cham- 
 berlin* to the character and connection of the kettle-mo- 
 raine in Wisconsin, and by Dr. George M. Dawson || to the 
 
 * See my paper in the " Proceedings of tlie Boston Society of Natural His- 
 tory," Tol. xix, pp. 60-6.S. 
 
 f "New Hampshire Geological Report," vol. iii, pp. 800-306. 
 t " Report upon the Geology of New Jersey for 1878." 
 
 * " On the Extent and Significance of the Wisconsin Eettle-Moraine." 
 
 I " On the Superficial Geology of the Central Region of North America," 
 from the "Quarterly Journal of the Geological Society," vol. xxxi, 1876. This 
 is a summary of a portion of the author's " Report on the Geology and Re- 
 sources of the Forty-ninth Parallel," 1875. 
 
BOUNDARY OF THE GLACIATED AREA. 135 
 
 significance of the extension of the Missouri coteau in Brit- 
 ish America, hopes were at once raised that a distinct line 
 of terminal moraines might be traced across the continent. 
 "With this theory in mind, the late Professor H. Carvill 
 Lewis and myself began the survey of Pennsylvania in 1881. 
 But, upon crossing the Alleghanies and pursuing the investi- 
 gations in the Mississippi Valley, I was compelled to aban- 
 don this view, and to be content with finding marginal de- 
 posits more evenly spread over the country, ending, in some 
 cases, in an extremely attenuated border. And, upon reflec- 
 tion, the fallacy in our original theory, that there must be a 
 terminal moraine — -that is, a noticeable ridge of glacial ac- 
 cumulations to mark the farthest extent of the ice — ^is easily 
 seen. 
 
 The extent of a glacial deposit at any particular point 
 will be determined by three factors, namely : 1. The amount 
 of accessible loose material in the line of glacial movement 
 which the ice can seize upon and transport. It is evident 
 that, if the rocks over which the ice moves are hard and 
 smooth and already denuded of loose material, there may 
 be much motion of ice with little transportation of soil. 
 2. The length of time during which the ice-front remains 
 at a given point, since time acts as a multiplier. 3. The 
 exemption of the deposit from the action of denuding agen- 
 cies. When a glacier melts, the torrents of water arising 
 may, in a short time, tear down and distribute as sediment 
 to distant valleys the material accumulated by the slow 
 movement of centuries. Indeed, it has been questioned by 
 some whether the larger part of the grist of the glacier has 
 not been thus transported far beyond the extreme limits 
 reached by the ice itself. This transportation by water from 
 the front of glaciers is certainly of immense extent. Every 
 subglacial stream is surcharged and milky-white with sedi- 
 ment as it emerges from the ice-front. As before stated, a 
 traveler in the State of Washington, from Portland to 
 Seattle, can detect the presence of glaciers in the Cascade 
 Mountains, scores of miles away, simply by the milky color of 
 
136 THE lOE AGE IN- NORTE AMERICA. 
 
 the streams crossed by the railroad. At Tacoma, on Puget 
 Sound, the milk-white water, coming down from distant gla- 
 ciers in Mount Tacoma, struggles with the dark-blue water 
 of the sound for the occupancy of the harbor, and gives the 
 surface of the bay the nondescript appearance of an im- 
 mense slice of marble-cake. As one passes the mouth of 
 the Stickeen Eiver beyond Fort Wrangel, in Alaska, the 
 line of demarkatioii between the clear waters of the ocean 
 and those of the glacier-laden currents of the river is as plain 
 as that between the water itself and the shore. One of the 
 most interesting occupations of the leisure hours of our long 
 encampment in Glacier Bay was to watch this struggle for 
 occupancy between the milk-white water of the four sub- 
 glacial streams pouring into the ialet, and the pure blue 
 waves urged against it by the recurring tides of the ocean. 
 With a rising tide of twenty-two feet, the line of demarka- 
 tion between the glacial water and the waters from the Pacific 
 moved alternately backward and forward over the inlet for a 
 distance of one or two miles, and in the shallow water, miles 
 away, the screw of the steamer brought to the surface great 
 quantities of the sediment which is rapidly filling up the bay. 
 When one considers the constancy of the operation of 
 this cause during all glacial time, he may well be pardoned 
 for regarding the glacial debris still remaining upon the con- 
 tinent as but an insignificant remnant of the total amount 
 transported and deposited by glacial action. During the 
 whole continuance of the Glacial period in E"orth America, 
 subglacial streams must have sent their turbid currents down 
 through every New England outlet, and through the Hud- 
 son, the Delaware, the Susquehanna, and all the northern 
 tributaries of the Mississippi. The terraces marking these 
 glacial water-courses retain simply a part of the coarser ma- 
 terial transported ; the fine material went constantly onward 
 to the sea, helping to build up the immense delta of the lower 
 Mississippi, and to line the whole coast of the Atlantic with 
 a deposit of fine sediment ready at some day to rise above 
 the surface as fruitful soil. 
 
BOUNDARY OF THE OLAOIATED AREA. 137 
 
 With these remarks, we are prepared to come to the spe- 
 cific subject of the present chapter, namely, the character 
 and extent of the glacial deposits marking the southern bor- 
 der of the glaciated area in North America. Through a por- 
 tion of the distance these accumulations are so marked as to 
 merit the name of terminal moraines. Through another 
 portion that name is hardly applicable to anything near the 
 glacial border. In a subsequent chapter there will be a dis- 
 tinct discussion of the whole question of moraines. In this 
 it is our purpose to follow some\diat minutely the boundary 
 of the area, and detail its various aspects. 
 
 OfE the coast of Maine the ice, at its culminating period, 
 extended an unknown distance into the sea, surmounting thb 
 eminences of Mount Desert and all that rock-bound coast, and 
 leaving its terminal deposits in- water so deep that there is 
 little hope of ever determining its exact situation. But in 
 southeastern Massachusetts the deposits emerge from the 
 water as true moraines, and offer themselves as most interest- 
 ing objects of study. Nantucket, Tuckemuck, Chappaquid- 
 dick, Martha's Vineyard, No Man's Land, and Block Island 
 are but portions of the extreme terminal moraine whose back 
 emerges at these points from the water. Cape Cod, from 
 Provincetown to Wood's HoU and the Elizabeth Islands, is a 
 similar remnant of a vast moraine formed after the ice-front 
 had withdrawn a short distance to the north. Indeed, the 
 whole of Plymouth and Barnstable counties is " made land," 
 as really as that of the Back Bay in Boston, only in the one 
 case the earth was dumped, day by day, from the laborer's 
 cart, and in the other year by year, from the melting front 
 of the continental ice-sheet. 
 
 It is an instance of misleading poetic license which per- 
 mits us to sing of the " rock-bound " shore upon which the 
 Pilgrim Fathers landed, for there are no rodf-bound shores 
 in southeastern Massachusetts. The hills which first greeted 
 the eyes of the Pilgrim Fathers are the irregular morainic 
 accumulations so frequently characteristic of glacial margins. 
 In this case the soil composing them consists of sand, gravel, 
 
BOUNDARY OF THE OLAOIATED AREA. 139 
 
 and bowlders which have been scraped off by the ice from 
 the mountains and ledges of New Hampshire and the inter- 
 vening portions of Massachusetts, transported to the glacial 
 margin, and there deposited in such quantities as to consti- 
 tute the whole southeastern portion of the latter State. The 
 three hundred and sixty lakes of Plymouth township are 
 nothing else than a cluster of kettle-holes. Manomet Hill, 
 southeast of Plymouth, is not a mountain which has been 
 thrust up by convulsive agencies, nor yet a remnant of a par- 
 tially eroded plateau, but a glacial deposit, hundreds of feet 
 in height and many miles in extent. From the fact of its 
 running nearly at right angles to the backbone of Cape Cod, 
 Manomet Hill is spoken of by some as a medial moraine. 
 But it is doubtful if it is necessary so to regard it. The re- 
 treat of a glacier, like the retreat of an army, is determined 
 in part by the nature of the opposing foe. In the present 
 instance there are abundant reasons for believing that the ice 
 retreated by the left flank ; for it is evident that the ocean 
 had much to do in setting bounds to the general southeastern 
 movement of the ice-sheet in New England. From the con- 
 tour of the coast, it can be seen at a glance that the waters of 
 the ocean had constant opportunity to eat in upon the ice 
 from the east as well as from the south. 
 
 Nantucket marks the extreme southeastern limit. Here 
 the ice maintained its position against opposing forces, until 
 the outer line of moraines just mentioned was built up. The 
 next line of defense taken up by the ice is that marked by 
 the backbone of Cape Cod. The retreat had been farthest 
 on the side most exposed to the ocean, and hence the dis- 
 tance between the moraine of Nantucket and that at South 
 Brewster is much greater than the distance between Martha's 
 Vineyard and Wood's Holl. The next line of defense taken 
 up by the ice-front along the course of Manomet Hill, left 
 Cape Cod and the whole shore of eastern Massachusetts open 
 to the undisputed sway of the ocean. 
 
 The two lines of moraine so clearly marked in south- 
 eastern Massachusetts can be readily traced westward through 
 
140 THE ICE AGE IN yORTH AMERICA. 
 
 a considerable portion of Long Island. The exterior line, 
 beginning at Montank Point, forms the backbone of the 
 island as far as Brooklyn, ]^. T., the city itself being built 
 upon it. The interior or parallel line, represented to the 
 east by the backbone of Cape Cod and the Elizabeth Islands, 
 disappears beneath the deeper waters of Buzzard's Bay, to 
 emerge upon the mainland at Point Judith in Rhode Island, 
 , and give variety to the whole coast of the State westward 
 from that point. This part of the moraine presents many 
 features of special interest at Watch Hill, Fishei-'s and Plum 
 Islands, and on the northern shore of Long Island as far as 
 Port JefEerson. Westward from Port Jefferson only the 
 external Mne of moraine hills is traceable, Staten Island in 
 New York Harbor being a most interesting development of 
 it. The northern and western portions of this island are 
 covered with the peculiar combination of rounded knobs and 
 circular depressions characteristic of moraines, while the 
 southeastern portion of the island was just beyond the reach 
 of the ice, and the deposits upon it are of an entirely differ- 
 ent character. 
 
 Up to this point in our investigations some doubt may 
 attach to the inferences concerning the limits of the great 
 ice-sheet. For, since the ocean everywhere expands to the 
 south, it may be asked. What certainty is there that its 
 waters do not cover a belt of glacial deposits still farther out 
 than those now visible ? No positive answer can be made to 
 this objection. But, on striking the coast of New Jersey 
 opposite Staten Island, a fair field of investigation is at once 
 offered, and doubt as to the substantial correctness of the 
 delineation farther on need be no longer entertained. The 
 line of moraine hills across New Jersey is a direct continua- 
 tion of these forming the backbone of Long Island, and 
 covering the northern half of Staten Island. Here they 
 form a sharp line of demarkation between the glaciated 
 region to the north and the unglaciated plains to the south. 
 Beginning at Perth Amboy, the moraine bends northward 
 through Earitan, Plainfield, Chatham, Morris, and Hanover, 
 
Strutrura j Co., Engr'a. N.y. 
 
 FiQ 45 The moraine according to Lewis and Wright. But the "Attenuated Border" 
 
 extended >>olow the mouth of the Lehigh. See Chapter VII, Continued. 
 
142 THE ICE AGE IN NORTH AMERICA. 
 
 to Rockaway, thence a little south of west to Belvidere on 
 the Delaware, a few miles above Easton. , The innumerable 
 throngs of passengers between New York and Philadelphia 
 can not, after their attention has been once called to the 
 facts, fail to notice this moraine as the southward-bound 
 trains pass through it, and emerge into a level, sandy region 
 free from bowlders and all irregular drift deposits. At Me- 
 tuchen and at Plainfield the transition is almost as clearly 
 marked as that between land and water. 
 
 Before following the terminal belt farther west, where 
 its characteristics are more or less disguised by the local 
 topography, we will pause to consider more carefully some 
 of the main characteristics of it as so far traced. 
 
 That these hills constitute a true moraine is evident from 
 the fact that they are composed of loose material such as, 
 both from the nature of the case and from observation, we 
 know is actually deposited wherever the front of a glacier 
 rests for any great length of time. A considerable portion 
 of them consists of material which has been transported 
 from various localities to the north, and deposited without 
 any stratification. Some of the bowlders are unworn and 
 angular, as if having been carried upon the back of the gla- 
 cier. Others are partially rounded and scratched in such a 
 manner as to show that they have been forced along through 
 the mass of sand and gravel which everywhere underlay the 
 moving field of ice. Sections, however, frequently show in 
 these hills a limited amount of stratification. But this is not 
 at all surprising, when we consider the manner of their f ormar 
 tion ; for the ice itself to a certain extent forms barriers to, 
 and furnishes channels for the ninning water which its own 
 melting provides, and so would itself afford the conditions 
 necessary to a partial stratification of its own deposits. 
 
 The terminal moraine where best developed may almost 
 be said to consist of innumerable ridges, knolls, and kettle- 
 holes. The kettle-holes are of all sizes, and are situated in 
 every imaginable position with reference to the general de- 
 posit; some of them, low down toward the base of the 
 
BOUNDARY OF THE GLACIATED AREA. 143 
 
 moraine, are tilled to the rim with water ; others are but par- 
 tially filled ; while others are for the greater portion of the 
 year completely dry. The angle at which the earth forming 
 their sides stands is usually as sharp as the nature of the 
 material will allow, and bowlders are as frequently found 
 upon the inside of the rim as upon the outside. 
 
 The origin of kettle-holes has already been explained ; 
 but it is in place here to remark upon some of the general 
 considerations supporting the theory already advanced.* It 
 is evident, from a'' inspection of the depressions themselves, 
 that they can noi, be the result of erosion, since the depres- 
 sions are too irregular and too deep to have been formed by 
 the plunging movement of water, and the material is too 
 coarse for a water deposit. In some respects kettle-holes 
 resemble what are called sink-holes, frequent in limestone 
 regions, where a great amount of material below the surface 
 is removed in solution, leaving numerous caverns whose roofs 
 eventually sink in, and form the depressions characteristic of 
 such regions. But kettle-holes abound in regions where no 
 such caverns could have been formed, and are distributed 
 over the country according to a method which could not have 
 originated by the action of underground currents of water. 
 
 While the iceberg theory was in favor to account for the 
 drift, it was not uncommon to hear these kettle-holes spoken 
 of as places where icebergs had stranded, and in turning 
 round and round had bored holes in the bottom of the ocean- 
 bed over which they were floating ; but, now that the ice- 
 berg theory is abandoned, and observations are more extended, 
 the origin of kettle-holes is readily understood as an inevita- 
 ble part of the glacial theory itself. Any one who will in 
 the early spring-time take pains to observe the melting of 
 masses of ice which have been covered by ashes and other 
 refuse, or which have been partially buried beneath the 
 debris of earth which some spring torrent has brought down 
 from a neighboring hill, will find before him a very perfect 
 
 * See above, p. 66 el seq. 
 
144 TEE ICE AOE IN NORTH AMERICA. 
 
 object-lesson as to the formation of kettle-holes. All the 
 elements for their production are there, in and beneath the 
 accumulated debris. As the heat slowly penetrates the pro- 
 tective covering, especially upon the sides, where it is the 
 thinnest, it melts the ice and thus undermines the earthy 
 material, which, in due time, slides down to the base, and 
 thus gradually leaves a cone of ice in the middle, surrounded 
 at the edges by a continuous ridge of dirt. Eventually the 
 ice all melts away, and a miniature kettle-hole is formed. So 
 far as I know, the application of this principle to the expla^ 
 nation of the extended phenomena under consideration was 
 first made by the late Colonel Whittlesey,* of Ohio, in study- 
 ing the Kettle range of "Wisconsin. How completely this 
 theory was confirmed by my study of the Muir Glacier, in 
 the summer of 1886, has already been related.f 
 
 To prevent misapprehension, it should here be remarked 
 that we have not intended to affirm that the whole bulk of 
 Martha's Yineyard and Long Island consists of glacial depos- 
 its. The nuclei of those islands certainly existed before the 
 Glacial period, for at Gay Head, on Martha's Vineyard, and 
 in the vicinity of Port Jefferson, on Long Island, and at 
 some other places, there are extensive beds of Tertiary clay 
 underlying the glacial deposits, and rising above the water- 
 level. The glacial deposits simply form a capping of more 
 or less thickness to these older ones. It is still true, however, 
 that the glacial deposits have determined, in the main, the 
 present topographical features. 
 
 In following the moraine.across New Jersey, we find that 
 beginning at the sea-level, its base rises to a height of more 
 than a thousand feet, where it crosses the Blue Hills of 
 western New Jersey; and everywhere its surface is character- 
 ized by the knobs and kettle-holes, whose manner of for- 
 mation has just been explained. 
 
 Crossing the Delaware River, these characteristic phe- 
 
 * Report upon "The Drift Formations of the Northwest," in 
 "Smithsonian Contributions to Knowledge" 1866 
 t See above, p. 57 et seq. 
 
146 THE ICE AGE IN NORTH AiJ ERICA. 
 
 nomena are developed in a marked degree upon the hills of 
 Northampton county. Pa., nmiiing up to the base of the Kit- 
 tatinny Mountain, some miles below the Delaware Water- 
 Gap. West of the mountain, in Monroe county, the valley 
 south of Stroudsburo- is for several miles tilled with the 
 
 Fig. 47.— a fjlaciated pfbttle. nntaral size, frnm the moraine on Pocono plateau. Penneyl- 
 vauia, two thoubaiul feet aliove tlie sea, iNIonroe county. The striie along the longest 
 diameter are well niarketl. 
 
 same characteristic ridges, knobs, and kettle-holes. On going 
 still farther west, and rising suddenly fifteen hundred feet to 
 the plateau of Pocono Mountain — the southern extension of 
 
BOUNDARY Oh' THE OLACIATED AREA. 147 
 
 the Catskills— we find still the same characteristic deposits 
 slightly moditied by the different conditions. A range of 
 hills, sweeping around this plateau for ten or twelve miles in 
 a magnificent semicircle open toward the south, was discov- 
 ered, in 1881, by Professor Lewis and myself to belong to the 
 extreme and true terminal moraine of the continental ice- 
 sheet. South of it one may go for miles upon a level, sandy 
 plateau (about two thousand feet above tide) without en- 
 countering a bowlder or any foreign material ; while the low 
 range of hille, seventy-five or a hundred feet in height, is 
 
 Fig. 48.— The previous pebble viewed from tlie edu:e, Tlie reversed side was free from 
 
 glacial marks. 
 
 literally formed of bowlders ; among which may readily be 
 recognized those of ffranitie origin, wrenched from ledges 
 hundreds of miles to the north, and transported hither across 
 the valley of the Mohawk or over the broad exj)anse of Lake 
 
H8 THE ICE A as IN NORTH AMERICA. 
 
 Ontario. Nicely ensconced within their wooded shores, there 
 are here also the numerous lakelets so often found occupying 
 kettle-holes, and forming the sources of streams which issue 
 from the mountain-side to water the valleys helow. There 
 are few more interesting regions in which to study an ancient 
 terminal moraine than the plateau of Pocono Mountain, be- 
 tween Tobyhanna and Tunkhannock townships, in Monroe 
 county, Pa. 
 
 Passing still farther westward, and descending to the 
 North Fork of the Susquehanna, twenty miles below Wilkes- 
 barre, we find a remarkable terminal accumulation of glacial 
 debris filling the valley to a great depth for some distance 
 above Beach Haven. In the immediate vicinity of the river, 
 which was one of the great lines of drainage during the Gla- 
 cial epoch, the material is more or less modified by water- 
 action ; but the unmodified moraine can be clearly traced far 
 up on either side of the valley. A few miles to the west- 
 ward, on the other side of Huntingdon Mountain, and but ten 
 or twelve miles south of the southern wall of the Alleghanies, 
 the line of terminal deposits can be traced past Asbury, 
 through a whole township and some miles beyond, up the 
 eastern side of Fishing Creek. Through all this distance, on 
 the east side of the creek, there is nothing upon the surface 
 but these irregular and confused features of a well-marked 
 terminal deposit ; while on the west side of the creek, not a 
 sign of glacial action can be seen. But suddenly, above the 
 town of Benton, the belt of confused deposits of stone and 
 gravel begins to descend the eastern side, and after crossing 
 the valley diagonally, rises, like a broken-down Chinese wall, 
 upon the western side. 
 
 It is important to make a cautionary remark at this 
 point. The boundary so far in eastern Pennsylvania as 
 here delineated is that which was determined by Professor 
 Levids and myself in 1881, but it became probable that 
 there was a small margin of error in our delineation; while 
 from Luzerne county on, the varied fortunes of the ter- 
 minal moraine are difficult of description. The north-cen- 
 
BOUNDARY OF THE GLACIATED AREA. 149 
 
 tral counties of Pennsylyania are covered with forests, and 
 are cut up into gorges extremely difficult of access. Never- 
 theless, in Lycoming county, upon a plateau at Eose Valley, 
 three or four miles to the east of Lyboming Creek, and sev- 
 eral hundred feet above it, large kettle-holes with their sur- 
 rounding ridges of gravel, and their accompanying bowlders 
 and striated rock-surfaces, are marked features of the land- 
 scape at a height of 2,000 feet above the sea ; while upon 
 the west side of the creek these features are totally absent 
 for some miles above. Similar developments are met, at 
 occasional intervals, all along the line of the great conti- 
 nental divide in Potter county, whence the waters flow to 
 the widely separated regions of the Gulf of St. Lawrence, 
 Chesapeake Bay, and the Gulf of Mexico. The same pro- 
 nounced features already described mark the terminus of the 
 great ice-sheet where it crossed the valley of the various tribu- 
 taries entering the Alleghany River from the north, in Cat- 
 taraugus county, N. Y. In that State these are specially 
 noticeable at Ellicottville, at Little Valley, and upon the 
 high lands upon either side of the Eastern Branch of Oone- 
 wango Creek near Randolph. As the glacial margin 
 swings back again to the Pennsylvania line, it is marked by 
 numerous and impressive accumulations in Warren county, 
 one of the most accessible and notable localities being where 
 it crosses the valley of Conewango Creek at Ackley, a few 
 miles above its junction with the Alleghany River at Warren. 
 Here the marginal line of glacial deposits may be clearly seen 
 as it descends from the highlands on the east diagonally to 
 the valley, filling it to a great depth, and rising over the hills 
 in its onward course to the southwest. At this point in the 
 valley, as at some other places which could be mentioned, 
 the northern side of the moraine is more abrupt than the 
 southern. 
 
 It was here that we made some of our first and most 
 exact discoveries as to the limit of the ice west of the AUe- 
 ghanies. Professor Lewis and myself, who were pursuing 
 the investigations together, had already learned the charac- 
 
150 THE ICE AGE IN NORTH AMEHIOA. 
 
 teristics of the great lines of glacial drainage extending to 
 the south of the glacial limit, and of which more particular 
 mention will be made in a future chapter ; but it was here 
 that we first detected the exact relation of these lines of glar 
 cial drainage to the great ice-movement. Coming up from 
 Warren toward the glacial boundary, the valley of the Cone- 
 wango is seen to be filled increasingly full of gravel deposits 
 arranged in terraces on either side of the small stream. The 
 height of these above the stream is sixty or seventy feet. At 
 first the gravel is rather fine, but is constituted largely of 
 water-worn granitic fragments, which could have come with- 
 in range of the stream only by glacial transportation from 
 the far north. On proceeding a few miles farther north, 
 these terrace deposits become more and more irregular, being 
 thrown up into great ridges, and at the same time the mate- 
 rial becomes less water-worn and much coarser. Below this 
 point we had searched diligently in the gravel for scratched 
 stones, but none were anywhere to be found. A mile or two 
 from Ackley, however, we began to find pebbles upon which 
 the glacial scratches could be dimly traced. They had been 
 partially water-worn, but had not been rolled far enough to 
 completely obliterate their glacial marks. Upon reaching 
 A,ckley, we found the whole valley occupied by a true gla- 
 cial deposit, terminating abruptly to the north, and through 
 which the stream had cut a narrow channel. The moraine 
 ridge, or dam, as we might call it, rises from 100 to 150 feet 
 above the present bed of the stream, and is equally well de- 
 veloped upon both sides. Scratched stones and. granitic frag- 
 ments abound, and it is well marked upon either side of the 
 creek by the characteristic kettle-holes. Above Ackley, for 
 many miles, the Oonewango pursues a sluggish course, and 
 is bordered by extensive marshy land. The explanation of 
 all this is that the ice-front remained for a somewhat pro- 
 tracted period at Ackley, allowing the large accumulations 
 immediately below to take place. But its retreat from Ack- 
 ley for many miles northward was too rapid to permit of any 
 marked terminal accumulations : 
 
CHAPTER VII. 
 
 (CONTINTTED.) 
 THE ATTENUATED BOEDER. 
 
 So far it has been thought best to adhere closely to the 
 delineation of the glacial margin through New Jersey and Penn- 
 sylvania as given in the report of Lewis and Wright in Vol. 
 Z of the Pennsylvania Survey. But in the preparation of 
 that report we were laboring under the false impression that 
 the extreme glacial margin was always marked by a distinct 
 moraine. This error was partially recognized by us in speaking 
 as Professor Lewis, especially, did, of a bordering "fringe" 
 of sporadic glacial deposits extending some distance farther 
 south than the line as marked on our map. The study of 
 this was taken up later by Professor Edward H. Williams and 
 carried on across the state with the result that the boundary 
 of the "fringe" or "attenuated border" was found to extend 
 on an average, about twenty miles farther south than our 
 "terminal moraine." Similar results were found to prevail 
 in New Jersey by Professor Salisbury, Professor A. A. Wright, 
 and myself. 
 
 To be specific: The extreme glacial limit in New Jersey 
 reached to an irregular line nmning from Bound Brook, a 
 little south of Plainfield, to Riegelsville, on the Delaware, a 
 few miles south of Easton, Pa. So far, land-ice evidently 
 extended at one time. The striated bowlders found by Profes- 
 sor Salisbury and others still farther south were doubtless 
 carried by floating ice when the land was depressed to the 
 extent of about 200 feet, of which evidence will be given in 
 a later chapter. 
 

 
BOUNDARY OF THE GLACIATED AREA. 153 
 
 In Pennsylvania it is interesting to note that the Alpine 
 plant Sedum Rhodiola, long known to exist in the narrows of 
 the Delaware River south of Riegelsville, marks the boundary 
 of the attenuated border in the extreme east. Thence the 
 line skirts the Triassic areas on the south side of the Durham 
 Valley, just south of Bethlehem, turns westward to the Schuyl* 
 kill at Berkeley a few miles north of Reading; thence north- 
 ward on the east side of the Schuylkill River to Shoemakers- 
 ville and going over the Blue Ridge Mountain in a zigzag 
 line, passes through Jacksonville and Kepner to Tamaqua 
 where it crosses the Schuylkill. Thence running westward it 
 crosses the Little Schuylkill at Wetherill Jimction four miles 
 from Pottsville depot, thence westward through Ashland 
 and Shamokin to the Susquehanna River a few miles south 
 of Selin's Grove. West of Pennsylvania this attenuated 
 border assumed greater and greater proportions, attaining its 
 largest extent in northeastern Kansas, from which fact the 
 deposits have been denominated "Kansan Drift." From the 
 thinness of the "Kansan" deposits and their more highly 
 oxidized condition, this drift has been assumed to be vastly 
 older than the deposits marked by the terminal moraine of 
 Lewis and Wright and, unfortunately, have given name to the 
 whole attenuated border and in popular apprehension carried 
 with it the assumption that they are all synchronous in age. 
 With this protest, however, it will be best to continue the 
 yse of the term and speak of these deposits as "Kansan" 
 and of the latest ones as "Wisconsin." 
 
 One of the most impressive facts ascertained by Professor 
 Williams concerning this earliest advance of the ice over the 
 region between the Lehigh and the Susquehanna valleys was 
 that of the formation of an ice-dam across the mouth of 
 the Lehigh at Easton, producing a temporary lake (which 
 might properly be named Lake Williams) extending from 
 Allentown to Topton and there overflowing into the Schuyl- 
 kill at B er keley a few miles above Rea ding. The depth of water 
 
154 THE ICE AGE IN NORTH AMERICA, 
 
 in this lake was 280 feet at AUentown and its outlet at Topton 
 was 500 feet above tide. The shore lines can easily be traced 
 along the whole distance. The overflow into the Schuylkill 
 carried floating ice and glacial debris into that river so that 
 considerable deposits of glacial material were made in some 
 places, notably at Norristown only a short distance above 
 Philadelphia. Much of the gravel in West Philadelphia is be- 
 lieved by Professor Williams to have colne down the Schuyl- 
 kill through this channel, and through the Little Schuylkill, as 
 all the coal region drained by the latter was covered by ice. 
 The efficiency and comparative recency of the glacial ac- 
 tion over this "Kansan" area in Pennsylvania is well shown 
 at Morea, a few miles north of Pottsville, and only one mile 
 north of the extreme limit of glaciation at this point. Here, 
 for commercial purposes, the "Mammoth bed" of anthracite 
 coal has been stripped of its covering of "Kansan till." The 
 coal vein here outcrops in nearly vertical planes favoring the 
 percolation of water and the disintegration of the surface. 
 Beginning at the top the covering consisted of from six to ten 
 feet of sandy till with occasional bowlders five feet in diameter; 
 below this were eighteen inches of crushed anthracite entirely 
 fit for the market ; then came three-fourths of an inch of rotten 
 coal mixed with angular specs of slate; then one inch of sandy 
 clay with rolled and angular quartzite and slate pebbles; 
 then one-half inch of fine bright crushed coal ; and below this 
 the glaciated surface, shown in the illustration, the upper 
 three-fourths of an inch of which was so soft and fully rotted 
 that it could be scratched with the finger nail. _ Below this 
 was an indefinite extent of solid bright marketable coal. The 
 recency of the glaciation appears in the fact that south of the 
 glacial border, only one mile away, the coal is so disintegrated 
 as to be worthless for many feet below the outcrop. At the 
 same time the covering in the glaciated- area is so sandy and 
 porous as to be very little protection to the surface of the 
 coal. 
 
-^'" 
 
BOUNDARY OF THE GLACIATED AREA. 155 
 
 Another noticeable characteristic of deposits over this 
 attenuated border is that the prevailing, highly oxidized mate- 
 rial is mingled with a considerable amount of fresh unoxidized 
 material brought from farther north, showing that the oxidi- 
 zation was mainly preglacial, and that the age of the deposit 
 must be reckoned from the accession of the fresh material. 
 In the effort to determine the age of these deposits from the 
 extent of the oxidization, it also should be ever kept in mind 
 that the ice moved first over an area whose surface had been 
 deeply disintegrated and oxidized during the long ages of 
 tertiary time. It was the product of this disintegration which 
 was first incorporated into the mass which was moved along by 
 the ice, and this naturally was carried farthest. Thecontribu- 
 tionsmade later were such fresher portions of therockysurface 
 as had been below the action of the disintegxating agencies of 
 the Tertiary period and so would be mingled with the earlier 
 material wherever the ice overrode the deposits of the primary 
 advance. 
 
 West of the Susquehanna the ice pushed over the plexus 
 of mountains south of Williamsport, rising to a height of 1,200 
 feet above the river and ending along a zigzag line bearing 
 northwestward, as shown in the map, reaching the west 
 branch of the river at Lock Haven. In this area several 
 most interesting and even startling results were produced. 
 Though the ice did not reach the valley of the Juniata River, 
 Professor I. C. White had reported at various places along the 
 border of the river, especially at Huntingdon "great heaps of 
 bowlder trash, both rounded and angular .... and 
 these often very much resemble genuine drift heaps." Some- 
 times these reach an elevation of 100 feet above the river. 
 Later, Professor Williams found unmistakable glaciated 
 stones in the corresponding high level terrace at Lewistown: 
 while on the western side of Warrior's Ridge a little above 
 Huntingdon, where the Juniata cut a narrow gorge through 
 the mountains there was a small deposit of erratics between 
 300 and 400 feet above the river. 
 
156 THE ICE AGE IN NORTH AMERICA. 
 
 All these facts became clear when it was known that the 
 ice crossed the Susquehanna and advanced to the summit of 
 the mountains lying between that river and the Juniata. The 
 glacial gravels at Lewistown came from a stream which poured 
 over the col at Adamsburg where the ice was arrested in its 
 movement. The bowldery deposits farther up the Juniata 
 near Huntingdon came from an immense glacial stream which 
 poured over the col between the head of Bald Eagle Creek and 
 a branch of the Juniata joining the main stream at Tyrone. 
 Bald Eagle Valley had been occupied by a long narrow glacial 
 lake occasioned by the obstruction of its mouth at Lock Haven, 
 where the depth of the water was 570 feet. The col above Ty- 
 rone has an elevation of 1,100 feet. The shore lines of this 
 temporary lake (which has appropriately been named Lake 
 Lesley) can easily be traced, and is marked by great cones of 
 gravel where tributary streams came in from the east. The 
 erratics throMTi up to such a great height on the west side of 
 Warrior's Mountain are evidently due to high and tumultuous 
 water produced by an ice-gorge where the stream enters 
 the narrow channel across the mountain ridge. Numerous 
 evidences of the damming of the West Branch of the Sus- 
 quehanna are to be found as far up as Emporium on the 
 Sinnemahoning River. 
 
 Northwestward from Lock Haven the border of the Kansan 
 drift is lost in the wildernesses of Lycoming and Potter 
 counties, becoming recognizable again near Coudersport, 
 beyond which it disappears under the moraine of Lewis and 
 Wright to reappear again on the highlands of Warren, Ve- 
 nango and Butler counties west of the Allegheny River where 
 the elevations rise above the flooded regions produced by the 
 ice-dams which reversed the drainage of the whole basin 
 west of the Alleghenies. A simple illustration shows the 
 probable overlapping of borders as suggested by Professor 
 Williams. 
 
 The history of the reversal of the drainage of the AUe- 
 
FiQ. so— Lake Lesley. E. Emporium. H. Harrlaburg. 3h. Sunbury. Wp. Wllllams- 
 port. Ty. Tyrone. 
 
 
 Fig. 51 — Advance of Wisconsin Ice over the Kansan Border near the apex of New York, 
 
158 THE ICE AGE IN NORTH AMERICA. 
 
 gheny might seem to be more appropriate to the chapter on 
 Glacial Dams, Lakes, and Waterfalls, but it is so intimately 
 related to the facts connected with the extreme extension of 
 the continental glacier in the Appalachian region that we 
 introduce it here, expecting the reader to refer to it again for 
 facts which have an important bearing on later theoretical 
 discussions. In itself, however, it is one of the most interesting 
 problems ever presented to the geographer and the geolo- 
 gist: I am permitted to quote freely from the unpublished 
 report of Professor E. H. Williams upon the subject, and to 
 make use of his extensive collection of facts. 
 
 LAKE ALLEGHENY. 
 
 Professor Williams writes, " 'Kansan' drift throughout 
 Pennsylvania is characterized by native copper. I have a 
 piece from Warren (40 feet below the surface), and farmers 
 have come to me at Bethlehem to come and see their 'cop- 
 per mine.' Mr. Albert G. Rau, Dean of the Moravian Col- 
 lege has, at numerous points, picked up rolled fragments 
 from 'Kaiisan' gravels. This seems to point to a Lake Su- 
 perior passage by the ice — Whence the glacier which first in- 
 vaded this part of the state came from the northwest, and 
 therefore moved against the drainage and presented so effect- 
 ual a dam that, with the exception of the hilltops, north- 
 western Pennsylvania and adjacent New York were sub- 
 merged by a lake whose eastern shores in Pennsylvania were 
 the highlands of Potter County and their extension south- 
 ward, while McKean County extended into it like a broad 
 promontory deeply gashed by its river systems. The name 
 Allegheny is proposed for this lake which originated long be- 
 fore the advent of glacial ice to the immediate region and 
 which, being but slightly drained subglacially, sent its wa- 
 ters southwards over the cols into other drainage systems. 
 As the glacier advanced it constricted the area of escape and 
 when it reached the line of the present Allegheny it formed. 
 
BOUNDARY OF THE GLACIATED AREA. 
 
 159 
 
 with the eastern highlands a trough through which the torrents 
 cut their way southward. The presence of high water sedi- 
 ment at Franklin shows that the col which imposed the height 
 to the lake was south of that place, and also shows that all 
 intervening cols were submerged and the drainage systems 
 
 Fig 62 — Lake Allegheny. B. Bamesvllle. C Clarendon. F. Franklin. I. Irvine. 
 O. Oil City. T. Thompsons. W. Warren. 
 
 between them aggraded. When the most distant and restrain- 
 ing col became degraded so that the interior ones came within 
 the area of scour they were cut down gradually and readily, 
 as the porous and loosely cemented sandstones rapidly yield 
 to water carrying only its own sands, and the shales carry 
 
160 THE ICE AGE IN NORTH AMERICA. 
 
 strata so highly jointed that they collapse under a slight im- 
 pact, and undermine the overlying and more resistant strata. 
 The result was an aggradation of older systems to the level of the 
 older cols and the present alternations of the old aggraded val- 
 leys with low angles of slope and gorges varying from a steep 
 V-shape to one with nearly vertical walls extending far below 
 the present water level and attesting to the torrential flows 
 which degraded them." 
 
 In estimating the significance of these facts, however, it 
 is important to bear in mind the extensive changes of land 
 levels which took place before, during, and after the Glacial 
 period. (1) It will be shown in a later chapter that there 
 was extensive elevation of the glaciated region in Tertiary 
 times increasing in extent towards the north. In all prob- 
 ability this amounted to more than 2,000 feet in the central 
 part of the glaciated area. This, in itself, may have had 
 something to do in reversing the drainage of many northerly 
 flowing streams. 
 
 (2) But at the close of the Glacial period the northerly 
 areas of the glaciated region were depressed so that they stood 
 at Montreal 600 feet lower than the present level, and farther 
 north still lower. It is impossible to tell how far south this 
 glacial depression extended in the northern part of the United 
 States. 
 
 (3) Since the retreat of the ice there has been a differ- 
 ential re-elevation of the glaciated area increasing towards 
 the north, and amounting to 600 feet at Montreal and 1,000 
 feet farther north. The axis about which this differential 
 re-elevation revolves seems to run east and west through 
 Central New York and the basin of Lake Erie. In estimating, 
 therefore, the height of the col, in the lower Allegheny or ; 
 middle Ohio Valley, which determined the level of Lake 
 Allegheny we must not forget that this differential northerly 
 depression during glacial times may make the water levels, 
 in the upper part of the lake appear to be higher than they 
 
BOUNDARY OF THE GLACIATED AREA. 161 
 
 absolutely were. But we will give the facts as they now 
 appear. 
 
 The facts will be best appreciated by somewhat detailed 
 study of the portion of the Allegheny Valley which, passes 
 through Warren and McKean counties in Pennsylvania and 
 Cataraugus County in New York. The upper Allegheny 
 descends from the high tableland of Potter and McKean 
 counties in a northerly direction, and consequently was 
 obstructed by the advancing ice, both of the Kansan and of 
 the Wisconsin epochs. Abundant evidence of the slack water 
 thus produced is seen all along this part of the valley, from 
 Coudersport and Keating through Port Allegheny and Turtle 
 Point dbwn to Salamanca in New York where the stream 
 turns abruptly to the south. But the evidences of a flooded 
 condition of the valley at the time of the extreme extension 
 of the ice still continues down stream well-nigh to the Ohio 
 River. Everywhere along the course of this valley fans of 
 gravel appear at the level of the glacial high water, wherever 
 tributary streams come in from a higher level. At Warren 
 this fan is 400 feet above the present water level and at Frank- 
 lin, 650 feet. 
 
 In the words of Professor Williams' report, "The affluents 
 of the Allegheny show traces of high water. Those flowing 
 from the glacier are generally aggraded and reversed: those 
 from the Pennsylvania highlands are also aggraded but with 
 local material. The narrowness of their valleys allowed the 
 removement of sediment when the water level brought the 
 bottoms within the area of scour, and it is only in favored 
 places that the evidences remain. Some, however, as Red 
 Bank Creek, and the Kiskiminetas-Conemaugh system show 
 abundant traces of deep sedimentation .... At times 
 the conjunction of sudden bends in the main stream and the 
 debouchment of short side valleys which branch from the same 
 area have caused eddies or deflections of the main stream and 
 have aggraded the side valleys so as to resemble portions 
 of a river channel at elevations higher than the present one." 
 
162 THE ICE AGE IN NORTH AMERICA. 
 
 The most interesting collection of facts appears in the 
 vicinity of Warren at the jimction of Conewango Creek and 
 the Allegheny River. With little doubt the preglacial drain- 
 age flowed from some distance south of Bamesville northward 
 through Clarendon and Warren into the Conewango and 
 thence on into the Lake Erie basin, and at a level considerably 
 lower than that of the present river. 
 
 The rock trough of the Conewango is much wider than that 
 of the Allegheny for several miles up the stream, showing that 
 the preglacial drainage was through the Conewango. This 
 greater breadth continues down the Allegheny to Irvine, and 
 thence up the Brokenstraw to the glacial limit. Below Irvine 
 the trough of the Allegheny again becomes constricted through- 
 out almost its entire course. Usually its lower rocky trough 
 below this point is not more than three-fourths as wide as it 
 is above Irvine, and at one point near Parker its width is 
 less than half that in the upper part of the valley. 
 
 But the broad preglacial trough of the Conewango ex- 
 tends across the Allegheny through Stoneham and Clarendon 
 to Bamesville. The gravel deposits here are of the most 
 interesting and significant character. East of Warren upon 
 a rock shelf 250 feet above the present stream there is an 
 extensive gravel deposit from twenty to fifty feet in thickness, 
 containing many Canadian pebbles, and continuous with 
 and forming a part of undisturbed gravel strata extending 
 down the side of the trough to the river level. It is note- 
 worthy also that the lower part of this deposit for a consider- 
 able depth is fine sand, and at the bottom blue clay, indicating 
 deposition in still water. Crossing the Allegheny to Stoneham 
 we find here also a gravel deposit overlying deposits of fine 
 sand and blue clay containing frequent logs of trees such as 
 now cover the hills, and extending to a depth of 160 feet 
 below the surface in the middle of the trough. South of this 
 is a cranberry swamp two or three miles in length extending 
 to Tiona, where we again meet a gravel deposit filling a 
 
BOUNDARY OF THE GLACIATED AREA. 163 
 
 buried valley as deep as that underlying the swamp and the 
 gravel at Stoneham. But while the Stoneham deposit con- 
 tains Canadian material, that from Tiona to Sheffield consists 
 wholly of local material which has been brought down from 
 the sides of the mountain to the east and south. 
 
 Here again an interesting thing occurs. The gravel 
 deposit between Sheffield and Barnesville rises to the level 
 of a col which leads through a precipitous gorge into and down 
 the Tionesta River reaching the Allegheny at the town of the 
 same name. But the northern branch of the present Tionesta 
 rises a considerable distance west of Stoneham; the deposit 
 at Stoneham being the watershed between that place and 
 the Upper Allegheny only a few miles to the north. From 
 Clarendon to Barnesville this branch flows over a preglacial 
 trough nearly 200 feet in depth, then the present stream 
 occupies for the rest of its course a narrow rocky trough bor- 
 dered only in a slight degree with gravel deposits. 
 
 The explanation of this, as already intimated, is that upon 
 the obstruction of the northerly flowing preglacial stream 
 through the Conewango Valley, deep slack water was produced 
 in the Upper Allegheny Valley, the depth being regulated by 
 the height of the highest col at the south. The depth of the 
 water at Clarendon and Warren was about 500 feet, as shown 
 by the depth of the buried rock bottom of the river at Warren 
 added to the height of the gravel terraces in the vicinity of 
 Clarendon. In such depth of water, held in check by an 
 obstructing col somewhere at the south the lower portions 
 were stagnant so that blue clay and fine quicksand would 
 settle and this is what is found to a thickness of about 200 
 feet. Above this approximate level coarse sand and gravel, 
 with occasional large pebbles, was spread in dumps and fans 
 wherever tributary streams brought in material, which was 
 pre-eminently the case where streams entered from the 
 glaciated region. Such are the terraces of glacial gravel 
 already described just east of Warren, and a still larger and 
 
164 THE ICE AGE IN NORTH AMERICA. 
 
 higher one a mile, or so, above the mouth of the Conewango 
 in the narrower valley of the Allegheny. 
 
 A still more interesting and significant dump lies about 
 one-half mile west from Clarendon where there is an extensive 
 gravel deposit running parallel to the valley and resting on 
 the older local slopes. The surface of this deposit is 160 feet 
 above the present level of the valley. Its depth, however, as 
 shown bynumerous driven wells is 308 feet, of which the upper 
 sixty feet is gravel containing a noticeable amount of granitic 
 material, underlaid by 148 feet of sand with a small amoimt 
 of gravel, and this in turn by 100 feet of clean clay. In this 
 clay the drill, in some cases, went through a stratimti of logs. 
 
 Anticipating, somewhat, the more comprehensive discus- 
 sions of the chapters on Preglacial and Glacial Drainage, the 
 order of events as indicated by the facts in this interesting 
 locality will be found to be as follows: 
 
 In early and middle Tertiary times the drainage of the 
 Allegheny and upper Ohio basins was northward while the 
 land levels were lower in the north than they were in the south . 
 During the later part of the Tertiary period an elevation of 
 land went on over all the region afterwards covered with 
 glacial ice, being greater in the north than inthesouth. This 
 differential elevation perhaps had much to do with the reversal 
 of the drainage lines of which we have such abundant evidence. 
 But the advance of the glacial ice front against the northerly 
 lines of drainage completed the reversal, so that unprecedented 
 floods of water poured over the cols between the reversed 
 channels, wearing them down with great rapidity as is shown 
 by the narrowness of the troughs and steepness of the sides 
 of the gorges through various sections of the present drainage 
 lines. The position of the highest col was probably a consider- 
 able distance below the upper end of the Ohio River not 
 unlikely a short distance below Wheeling, W. Va., as suggested 
 by Chamberlin. 
 
 In this view, the rock erosion of the Allegheny and Ohio 
 
BOUNDARY OF THE GLACIATED AREA. 
 
 165 
 
 valleys is mainly preglacial, and the high level gravel terraces 
 which line the troughs through their entire extent were de- 
 posited during the various stages of this rock erosion. The 
 
 Fig. 53, — Map of Upper Allegheny Valley, Pa. 
 
 difficulty of accepting this hypothesis, arising from the fact 
 that it involved believing that the deposition of the high 
 level terraces went on without the filling of the lower and 
 
166 THE ICE AGE IN NORTH AMERICA, 
 
 narrower portions of the rock gorges through which the stream 
 runs, was met by the sagacity of Professor E. H. Williams, 
 whose intimate knowledge of the subject obtained as a hy- 
 draulic and mining engineer has enabled him to make the 
 whole process clear. This is checked by the fact that the 
 planes of sedimentation uniformly follow the contours of 
 the underlying rocks and show that, first, those contours 
 were carved out before the deposition began and, second, 
 that the later sediments poured over them as in the case of 
 ordinary bars and fans and varied from coarse to fine with 
 the velocity of the current. 
 
 As tidal currents scour out and keep clear certain channels 
 where their action is concentrated, so a powerful river tor- 
 rent scours out its main channel to a great depth, while it 
 throws up and deposits its sediment both coarse and fine upon 
 the higher bordering levels whenever there is a bend in the 
 trough changing the course of the current, or wherever there 
 is a strong tributary coming in at a broad angle. The forces 
 involved are nothing other than those which form an ordinary 
 flood plain, except that they are extremely vigorous. On 
 following down the Allegheny and Ohio valleys all the high 
 level gravel terraces can be accounted for by the action of 
 the tumultuous torrents from the melting ice of the closing 
 stages of the Glacial period as they poured through the 
 tortuous channel as it now exists. 
 
Fig. ."i 1— S:irnl pit ut Warren, showing b:.ir oq top of yl;u'k walL^r sands. 
 
 Fro. 55 — Bar at ^Varrcn, showing bedding and elevation abovo Warren. 
 
CHAPTER VTI. 
 
 (concluded) 
 
 THE GLACIAL BOUNDARY WEST OF PENNSYLVANLA.. 
 
 Through Columbiana county, Ohio, as in the adjoining 
 counties of Pennsylvania, there is, to the south of the heavj- 
 accumulations of till, a fringe of thinner glacial deposits from 
 one to three miles wide. Over this margin there are scat- 
 tered evidences of glacial action, consisting of granitic bowl- 
 ders and patches of till here and there upon the highlands, 
 
 * See G. F. Wright, " The Glacial Boundary in Ohio. Indiana, and Ken- 
 tucky," Western Reserve Historical Society; also "Ohio Geological Report," 
 Tol. V, pp. 750-771 ; T. C. Chamberlin, " Extent, etc., of the Wisconsin Ket- 
 tle Range " (" Transactions of the Wisconsin Academy of Sciences," vol. iv) ; 
 "Geological Survey of Wisconsin," vols, ii and iii (Madison, 1877-'80); "Pre- 
 liminary Paper on the Terminal Moraine of the Second Glacial Epoch " (United 
 States Report); George H. Cook, "Annual Reports for New Jersey for 1877, 
 1878"; G. M. Dawson, "On the Superficial Geology of British Columbia" 
 (" Quarterly Journal of the Geological Society, 1878," vol. xxxv, p. 89); J. W. 
 Dawson, "Changes of the Coast-Level in British Columbia' ("Canadian Natu- 
 ralist," April, 1877); G. K. Gilbert, "On Certain Glacial and Post-Glacial Phe- 
 nomena of the Maumee Valley, Ohio" ("American Journal of Science, 1871," 
 vol. ci, p. 339) ; C. H. Hitchcock, " Moraines of North America " (" Popular Sci- 
 ence Monthly," 1881) ; Clarence King, " United States Geological Explorations of 
 the Fortieth Parallel," vol. i ; " Systematic Geology " (Washington, 1878); Lewis 
 and Wright, " Report on the Terminal Moraine in Pennsylvania and Western 
 New York, Second Geological Survey of Pennsylvania, Z " ; Warren Upham, 
 " The Northern Part of the Connecticut Valley in the Champlain and Terrace 
 Periods" ("American Journal of Science, 1877," vol. cxiv, p. 459); "The For- 
 mation of Cape Cod" ("American Naturalist, 1879," vol. xiii, pp. 489, 652); 
 " Geological Survey of New Hampshire," vol. iii (1878) ; " Geological and Natu- 
 ral History Survey of Minnesota" (Report for 1879); "Terminal Moraines of 
 the North American Ice-Sheet" ("American Journal of Science, 1879," vol. 
 cxviii, pp. 81, 197); Charles Whittlesey, "Fresh-Water Drift of the Northwest- 
 ern States" ("Smithsonian Contributions, 1866," vol. xv); N. H. Winchell. 
 "The Drift Deposits of the Northwest" ("Popular Science Monthly," vol. iii, 
 pp. 202, 286); "Geology of Minnesota" (Annual Reports, 1872, etc.). 
 
 *See also full lists given in the Appendix. 
 
168 
 
 THE IGE AQE IN NORTH AMERICA. 
 
 at an elevation of from 300 to 500 feet above the OMo 
 River. North of this fringe the till is continuous, and every- 
 where of great depth. At Palestine, on the eastern edge of 
 the county, and at New Alexandria, near the western side. 
 
 Fia. 56. — Map of the glaciated region of Ohio, showing a part of ita extension in 
 Kentnclcy. 
 
 wells are reported in the till fifty feet deep. This is upon 
 the highest land in that part of the country, and the glacial 
 deposits are marked, in a moderate degree, by the knobs and 
 kettle-holes characteristic of the moraine upon the south shore 
 of New England. A mile or two west of Canton, in Stark 
 
BOUNDARY OF THE GLACIATED AREA. 169 
 
 county, the accunnilations of glaciated material are upon a 
 scale equal to anything upon Cape Cod. The northern part 
 of Holmes county is covered with till, which is everywhere 
 of great depth, and in numerous places near the margin dis- 
 plays, though in a moderate degree, the familiar inequalities 
 of the New England moraine. After the southern deflec- 
 tion in Knox county, the glaciated region is entered near 
 Danville, from the east, on the Columbus, Mount Vernon, 
 and Akron Railroad, through a cut in till a quarter of a 
 mile long, and from thirty to forty feet in depth. At the 
 old village of Danville, near by, upon a neighboring hill, 
 wells are reported as descending more than a hundred feet 
 before reaching the bottom of the till. Through Licking 
 county, both north and south of Newark, the depth of the 
 glacial envelope is great up to a short distance of its east- * 
 em edge. At the old canal reservoir, in Perry county, the 
 characteristic features of a moraine come clearly out. The 
 hill just to the south of this, on which Thornville is built, is 
 a glacial deposit in which wells descend from thirty to fifty 
 feet without striking rock. This is upon the highest land 
 in the vicinity. The reservoir itself seems to be simply a 
 great kettle-hole. AH through Fairfield county the glacial 
 accumulation is of a great depth down to within a very short 
 distance of its margin. 
 
 But perhaps the most remarkable of all the portions of 
 this line in Ohio is that running from Adelphi, in the north- 
 east comer of Ross county, to the Scioto River. The accu- 
 mulation at Adelphi rises more than two hundred feet above 
 Salt Creek, and continues a marked feature in the landscape 
 for many miles westward. Riding along on its uneven 
 summit, one finds the surface strewn with granitic bowlders, 
 and sees stretching off to the northwest the magnificent and 
 fertile plains of Pickaway county, while close to the south of 
 him, yet separated by a distinct interval, are the cliflEs of 
 Waverly sandstone, rising two hundred or three hundred 
 feet higher, which here and onward to the south pretty 
 closely approach the boundary of the glaciated region. 
 
170 THE ICE AGE IN NORTH AMERIOA. 
 
 Through the southeastern corner of Highland county, and 
 the northwestern comer of Adams, the terminal accumula- 
 tions are less marked than in Ross county ; still, their bound- 
 ary can be accurately and easily determined. It approaches 
 the Ohio River, in the vicinity of Ripley and Higginsport in 
 Brown county, and crosses it from Clermont county, entering 
 Kentucky half a mile north of the line between Campbell 
 and Pendleton counties in that State. Cincinnati was cov- 
 Bred with ice during a portion of the period. There are un- 
 doubted glacial deposits within the bounds of the city at the 
 railroad station at Walnut Hills, and near Avondale, at a 
 height of about four hundred feet above the river. At North 
 Bend, twenty miles below Cincinnati, the tunnel of the rail- 
 road leading from the Ohio to the Great Miami River is 
 through an indubitable glacial accumulation which rises two 
 hundred feet above the river. The northwestern part of 
 Boone county, Ky., was also covered with the ice to a dis- 
 tance of several miles south of the Ohio River. 
 
 Through Indiana the glacial boundary, after following 
 tlie Ohio River to within ten or twelve miles of Louisville, 
 Ky., suddenly bends to the north, leaving a large triangular 
 portion of the State unglaciated. The base of this ungla- 
 ciated triangle extends from Louisville to the Illinois line, 
 and its apex is about thirty miles south of Indianapolis. 
 The exact course of this part of the boundary is along a line 
 running from the neighborhood of Louisville northward 
 through Clark, Scott, Jackson, Bartholomew, and Brown 
 counties to Martinsville in Morgan county, where it again 
 turns west and south nearly parallel with, and west of, the 
 West Fork of White River, through Owen, Greene, Knox, 
 Gibson, and Posey counties, crossing the Wabash River 
 into Illinois, near Kew Harmony, the seat of Owen's cele- 
 brated socialistic experiment. 
 
 In Illinois the line continues in a southwesterly direction 
 through White, Gallatin, Saline, and Williamson counties, 
 where it reaches its most southern limit near the northern 
 boundary of Johnson county, fifty or sixty miles north of 
 
BOUNDARY OF THE GLACIATED AREA. 
 
 171 
 
 Cairo, a little below latitude 38°. From Williamson county 
 it starts westward upon its final course to the north, reaching 
 the Mississippi Kiver, near Grand Tower, in Jackson county. 
 From this point to the vicinity of St. Louis the Mississippi 
 runs nearly southeast, so that the glacial boundary in its 
 
172 THE ICE AGE IN SORIH AMERICA. 
 
 northwest course is coincident with the blufEs on the north- 
 east side of the river through Jackson, Randolph, and Mon- 
 roe counties, 111. 
 
 So far I have traced the bouthern boundary myself, and 
 the iufonnation here given is nearly all at first hand. Beyond 
 the Mississippi competent members of the United States 
 Geological Survey have traced the course approximately to 
 the Pacific Ocean. From these data we know that across 
 the State of Missouri the Missouri Itiver approximates closely 
 to the glacial limit. The line enters Kansas a little south of 
 Kansas City, and runs nearly west for a hundred miles to 
 the vicinity of Topeka, where it curves northward, crossing 
 the State of ITebraska about one hundred miles west of the 
 Missouri River, and reaching the southern hne of Dakota, 
 near the junction of the Niobrara and the Missouri. In 
 eastern Kansas and Nebraska the exact limits of the glaciated 
 area appear, from the reports, to be somewhat ditficult of 
 determination. It would seem that the action of water and 
 floating ice was predominant in determining the character 
 of the glacial deposits over that region, and the theory is 
 plausibly suggested by Professor Todd that the extension 
 of the ice beyond the Missouri formed glacial dams across 
 the valleys of the Kansas and Platte Rivers, so as to 
 maintain for a short period temporary lakes of a consid- 
 erable extent, which received and distributed the bowlder- 
 laden fragments of ice, as well as the finer elements of the 
 glacial deposits. The most of the glaciated portion of these 
 Stites is deeply covered with tine loam, or loess, which is 
 probably a water deposit, and, as we shall hereafter see, is on 
 good grounds believed by ChamberUn and Salisbury to be 
 an " assorted variety of glacial silt directly derived from gla- 
 cial waters." * 
 
 Through Dakota the glaciated region is bounded by a line 
 which runs northward from near the junction of the Niobrara 
 
 * " Prelimiaary Paper on the Drif tleas Area of the Upper Mississippi Val- 
 ley," by Thomas C. Chamberlin and Rollin D. Salisbury, in the "Sixth Annual 
 Report of the United States Geological Survey," p. 304. 
 
BOUNDARY OF THE OLAOIATED AREA. 
 
 173 
 
 and Missouri Rivers, and keeps pretty close to the west edge 
 of the river trough as far up as the month of the White 
 River. Beyond this it breaks over the western edge of the 
 trough for a short distance, and keeps approximately parallel 
 with the river, from five to ten miles west of it, until reach- 
 
174 THE IGE AGE IN NORTH AMERICA. 
 
 ing the vicinity of Oahe, a few miles above Pierre, at the 
 mouth of Bad River. From this point to the mouth of the 
 Cheyenne glacial deposits do not encroach upon the plateau 
 to the west. But, above the mouth of the Cheyenne, the 
 line strikes off farther west, and crosses the Moreau River 
 about forty-five miles back from the Missouri, and the Grand 
 and Cannonball Rivers at about the same distance. The 
 Northern Pacific Railroad passes from the glaciated to the 
 unglaciated region at Sims Station, about thirty miles west 
 of Bismarck. 
 
 In the chapter upon " Terminal Moraines " we will speak 
 more fully of the portion of Dakota lying east of the Mis- 
 bouri River ; but west of the Missouri the deposits belong to 
 what we have denominated the fringe, or what President 
 Chamberlin perhaps more appropriately calls " the attenuated 
 border." This portion of the boundary I had the privilege of 
 studying in the summer of 1888, driving some hundreds of 
 miles through the Indian reservation, extending from Fort 
 Yates southwestward to the Moreau, and thence southeast- 
 ward to the vicinity of Pierre. Here I found the border, 
 although somewhat attenuated, to be pretty sharply defined. 
 The glacial marks, however, consisted almost wholly of 
 bowlders and rather coarse gravel, and was pretty evenly dis- 
 tributed over the surface of the plateau. The formation of 
 the region is cretaceous, so that it is easy to recognize the 
 Laurentian bowlders. In size these sometimes attain a diame- 
 ter of four or five feet, and frequently almost cover the 
 ground. The elevation attained by them runs up to about 
 six hundred feet above the river. We found, however, no 
 scratches upon these bowlders, nor were there any exposures 
 of till or unstratified deposit, so characteristic of the terminal 
 moraine and of the central portion of the glaciated area. 
 But from my own experience I have no hesitation in classify- 
 ing these deposits with those produced by direct action of the 
 glacier. They are what would naturally occur on the attenu- 
 ated margin of the ice-sheet. 
 
 I found evidence, also, of a temporary line of marginal 
 
BOUNDARY OF THE GLACIATED AREA. 175 
 
 drainage, which consisted of a broad, level-topped gravel 
 deposit from four hundred and fifty to five hundred feet 
 above the present bed of the Cheyenne River.* This old river- 
 bottom is about two miles wide, and, where we crossed it, 
 extended as far as the eye could reach both up and down the 
 valley. Subsequently Mr. Eiggs found that it joined the 
 valley some miles above from the northwest. The gravel is 
 rather fine and well worn, and there is only an occasional 
 bowlder from one to two feet in diameter to be found upon 
 the surface. On the higher levels there are no traces of the 
 deposit. It has, therefore, as already said, the appearance of 
 marking a marginal line of drainage, which, north of the 
 Moreau River, was thirty or forty miles west of the Missouri, 
 but which joined the Cheyenne just west of Fox Ridge, and 
 followed that valley down to the vicinity of the Missouri, 
 and ever after kept near its trough till the river passed out of 
 the Territory at the Nebraska line. 
 
 Soon after crossing the Northern Pacific Railroad in 
 Dakota, the glacial boundary turns abruptly to the west, 
 crossing the Yellowstone in Montana near Glendive. We 
 give the delineation beyond this point in the words of Presi- 
 dent Chamberlin : 
 
 " Passing north of the Judith Mountains, it again touches 
 the Missouri in western Montana, near the mouth of the Ju- 
 dith River, but at once svtdngs away to the southward, to again 
 strike and cross the river forty miles above Fort Benton, and 
 about the same distance from the Rocky Mountains. Thence 
 it curves rapidly to the northward, crossing the national bound- 
 ary at the very foot-hills, and thence skirts them northward 
 to the limits of present determination. This is the outline 
 of the great northeastern sheet of drift. Along the Rocky 
 Mountains, within the United States, it bariely comes in contact 
 with demonstrable glacial formations from the adjacent mount- 
 ains, though widely intermingled with mountain ' wash.' " f 
 
 * The elevations are kindly furnished me by Rev. Thomas L. Riggs, of Oahe. 
 f " Proceedings of the American Association for the Advancement of Sci- 
 ence," vol. XXXV, 1886, pp. 196, 197. 
 
176 THE ICE AGE IN NORTH AMERICA. 
 
 In the chapter upon " Terminal Moraines " we will speak 
 of the extension of the Missouri coteau into British America, 
 as determined by Dr. George M. Dawson. But, while this 
 coteau is the limit of the heavier accumulations of Laurentian 
 drift, it is evidently not the limit of the extent of glacial ice, 
 for over an indefinite border to the west of it there is, accord- 
 ing to Dr. Dawson, a large percentage of Laurentian mate- 
 rial, amounting to nearly fifty per cent of the surface accumu- 
 lations, mingled with about the same proportion of quartzite 
 drift brought down from the Kocky Mountains by the numer- 
 ous streams originating in them. Dr. Dawson says that these 
 Laurentian and eastern limestone bowlders continue to occur 
 to within twenty-five miles of the base of the Rocky Mount- 
 ains, and up to a height of 4,200 feet above tide. The dis- 
 tance of these traveled blocks from the nearest part of the 
 Laurentian region is about 700 miles. Beyond this point, to 
 the west, eastern and northern rocks are not found. The 
 elevation of this marginal drift is about 2,000 feet above the 
 present height of the Laurentian plateau from which it came.* 
 
 "To the westward, in the valleys of Flathead, Pend 
 D'Oreille, and Osoyoos Lakes, and of Puget Sound, are 
 massive deposits of drift, partly of northern and partly of 
 iocal mountainous derivation. The Pend D'Oreille and 
 Puget Sound deposits appear unquestionably to be tongues 
 of the drift of British Columbia, which, if not constituting 
 a continnous mantle, at least passes beyond the character of 
 simple local mountain drift." f 
 
 In the Rocky Mountain region and to the westward there 
 were formerly extensive glaciers in Montana, Wyoming, 
 Colorado, Utah, Nevada, and California, where now they are 
 almost entirely absent. But the glaciation of this region was 
 never general. According to "Whitney, there are no signs 
 of ancient glaciers in western Nevada, though some of the 
 mountains rise to a height of 10,000 feet. In the east Hum- 
 
 * See the " Quarterly Journal of the Geological Society," vol. xxxi, 1875, 
 f See Chamberlin, as above. 
 
BOUNDARY OF THE GLACIATED AREA. 177 
 
 boldt range, local glaciers once existed in all the higher por- 
 tions. In some of the valleys they extended for seven or 
 eight miles. In Utah the Wahsatch Mountains were the 
 chief center of local glaciers. The principal mountain-mass 
 is about fifteen miles wide, and peaks above 1 0,000 feet high 
 are numerous. Tha glaciers formerly radiating from this 
 mass did not, however, reach a very low level. In Colorado 
 there are evidences of former glaciers only above the 10,000- 
 foot line. Beyond that line, such valleys as those occupied 
 by the head-waters of the Platte and Arkansas Rivers were 
 once filled with glaciers whose terminal moraines, in some 
 cases, formed dams of great extent, and thus gave rise to 
 temporary lakes. The most southern point at which signs 
 of local glaciers in the Rocky Mountains have been noted is 
 near the summits of the San Juan Range in southwestern 
 Colorado. Here a surface of about twenty-five square miles, 
 extending from an elevation of 12,000 feet down to 8,000 
 feet, shows every sign of the former presence of moving ice. 
 Northward of Utah and Colorado the signs of former glacia- 
 tion are also of the same local character — that is, glaciers 
 everywhere radiated from the higher mountain-masses, and 
 extended a short distance down the canons and valleys. The 
 Upper Canon of the Yellowstone, in the famous park, was 
 filled with glacial ice to a depth of 1,600 feet, and glacial 
 marks were abundant down to the vicinity of Livingston. 
 
 The glaciers of the Sierra Nevada and Cascade Range in 
 California, Oregon, and State of Washington were on a 
 much grander scale than those in the Rocky Mountains; 
 but, in the one case as in the other, the glaciated areas are 
 local, and, except in the state of Washington, not connected 
 with the grand movement fartlier north. 
 
 Upon tliis point Mr. Clarence King, who had most care- 
 fully explored the region, writes : 
 
 In the field of the United States Cordilleras, we have so 
 far failed to find any evidence whatever of a southward-mov- 
 ing continental ice-mass. As far north as the upper Colum- 
 
178 THE ICE AGE IN NORTH AMERICA. 
 
 bia Eiver, and southward to the Mexican boundary, there is 
 neither any bowlder-clay nor scorings indicative of a general 
 southward-moving ice-mass. On the contrary, the great areas 
 of Quaternary material are evidently subaerial, not subglacial. 
 The rocks outside the limit of local mountain glaciers show no 
 traces either of the rounding, scoring, or polishing which are 
 so. conspicuously preserved in the regions overridden by the 
 northern glacier. Everything confirms the generalization of 
 Whitney as to the absence of general glaciation. 
 
 Wherever in the fortieth parallel area a considerable mount- 
 ain-mass reached a high altitude, especially when placed where 
 the Pacific moisMire-laden wind could bathe its heights, there 
 are ample evidences of former glacial action, but the type is 
 that of the true mountain glacier, which can always be traced 
 to its local source. In extreme instances, in the Sierra Nevada 
 and Uintah Ranges, glaciers reached forty miles in length, and, 
 in the case of the Sierra Nevada, descended to an altitude of 
 3,000 or 2,500 feet above sea-level. Over the drier interior 
 parts of the Cordilleras the ancient glaciers usually extended 
 down to between 7,000 and 8,000 feet above the sea. In the 
 case of the Cottonwood Glacier of the Wahsatch, a decided ex- 
 ception, the ice came down to an altitude of 5,000 feet. . . . 
 
 Not more than a thirtieth part of the entire surface of the 
 fortieth parallel area was ever covered by glacial ice. It is 
 characteristic of the caflons of these extinct glaciers that they 
 give evidence of a gradual recession of the ice from its greatest 
 extension until it is entirely melted. This retiring from its 
 greatest bulk was not a continuous retrogression, but was 
 marked by pauses at certain places long enough to permit the 
 accumulation of considerable terminal moraines. In ascend- 
 ing one of the larger caflons, as of the southern Uintah, there 
 is observed a series of successive terminal moraines, and in 
 passing to the upper heights of the ranges it is found that, in 
 the great snow amphitheatres, glacial markings, rock-polish- 
 ing, and the arrangement of morainal matter are evidently 
 fresher than in the lower levels or points of greatest exten- 
 sion. 
 
 Whatever the greater causes may have been, the Cordilleran 
 surface south of the State of Washington was free from an ice- 
 
BOUNDARY OF THE GLACIATED AREA. 179 
 
 sheet, and the only ice-masses were small areas of local glaciers 
 which did not cover two per cent of the mountain country. 
 
 Supposing the arctic land configuration to be as now, and 
 a new oscillation of climate to bring on the conditions of a 
 glacial period, it is certain that the present ice-masses would 
 form the nuclei of new northern ice-fields, and Greenland 
 would probably be the point from which the glaciers would 
 move southward to cover eastern America ; and the absolute 
 distance from_ such a center would have something to do with 
 the failure of the ice to override the Cordilleras. Dawson's 
 suggestion of a great center of dispersion in Alaska, where an 
 elevated and broad highland fronts the moisture-laden ocean- 
 wind, has, it seems to me, a high degree of probability in ac- 
 counting for the southerly-moving ice of British Columbia with- 
 out recourse to that refuge of pure imagination, a polar cap.* 
 
 "With this agrees the testimony of Mr. I. C. Russell, in 
 his report on the " Quaternary History of Mono Valley, 
 California," the advance sheets of which I have been kindly 
 permitted to see. He writes : 
 
 The Sierra Nevada during the Glacial epoch was covered by 
 an immense neve field, which probably stretched continuously 
 from a little north of latitude 36° nearly to latitude 40°. The 
 width of this belt of perpetual snow must have been irregular, 
 conforming to the present topography of the summit of the 
 range, but it probably had an average width of between ten 
 and fifteen miles. Prom beneath this snowy mantle trunk gla- 
 ciers flowed both east and west down the flanks of the range. 
 
 The evidence is such as abundantly to justify the conclu- 
 sion that the ancient glacial system of the Sierra Nevada was 
 local, and had no connection with a northern ice-sheet. The 
 glaciers were clustered about and radiated from the higher por- 
 tion of the range in the same manner as from the contempo- 
 rary neve fields of the Wahsatch and Uintah Mountains, f 
 
 * " Systematic Geology " in the " United States Geological Exploration of 
 the Fortieth Parallel," 1878, pp. 459-461, 464. 
 
 f See the " Eighth Annual Report of the United States Geological Survey," 
 pp. 327, 328. 
 
180 THE lOE AGE IN NORTH AMERICA. 
 
 The ancient area of glaciers in' the Sierra Nevada Mount- 
 ains was chiefly confined to the western slope, and was most 
 remarkable in Tulare, Fresno, Mariposa, and Tuolumne coun- 
 ties, California, where, as we have seen, glaciers still continue 
 to exist. There are abundant marks of these ancient ice- 
 streams in the upper valleys of Kings, San Joaquin, Merced, 
 and Tuolumne Rivers. In the Tuolumne the glaciers were in 
 some places several miles wide and twelve hundred feet deep, 
 and extended as much as forty miles down the-vaUey. Gla- 
 ciers likewise filled the Yosemite Yalley on the Merced 
 Kiver. It is a mistake, however, according to Whitney, to 
 suppose that the Yosemite was formed, or indeed greatly 
 modified, by glacial action.* The vertical walls and the rect- 
 angular recesses are siich as to indicate the action of disrupt- 
 ive rather than erosive agencies in their formation. 
 
 The uorth-and-south valley between the Cascade Mount- 
 ains and the Coast range, in the State of Washington, is about 
 one hundred miles wide. The northeru half of this is pene- 
 trated by the innumerable channels and inlets of Paget 
 Sound, which extends from Port Townsend south about 
 eighty miles to the parallel of Mount Tacoma. The Olym- 
 pian Mountains to the west rise to a height of about ten 
 thousand feet, as does Mount Baker in the Cascade Range to 
 the northeast. The shores and islands of Puget Sound have 
 every appearance of being portions of a vast terminal mo- 
 raine. They rise from fifty to two hundred feet above tide, 
 and present a mixture of that stratified and unstratified ma- 
 terial characteristic of the terminal accumulations of a great 
 glacier. No rock in place appears anywhere about the sound. 
 Bowlders of light-colored granite and of volcanic rocks are 
 indiscriminately scattered over the surface and imbedded in 
 the soil. One of these bowlders, near Seattle, two hundred 
 feet above the sound, measures twenty feet in diameter, and 
 twelve feet out of ground. The channels of the sound and 
 
 * "The Yosemite Guide-Book," p. 83. See also the opinion of Mr. Russell 
 given near the close of Chapter X. 
 
BOUNDARY OF THE GLACIATED AREA. 
 
 181 
 
 of the adjacent fresh-water lakes have a general north-aiid- 
 south direction, parallel with the axis of the valley. This is 
 specially noticeable near Seattle, where Lake Washington, 
 
 Fig. M. — Tyi>ical section of till in Seattle. State of Warihingtou, about two hundred feet 
 above the sound. This is on the height between the .sound and Lake Washington. 
 
 elevated sixteen feet above tide, and twenty-five miles long, 
 is strictly parallel with the sound, and is separated from it 
 
182 
 
 THE ICE AGE IN NORTE AMERICA. 
 
 by a series of ridges showing every mark of glacial origin. 
 Not only is the surface of these ridges covered with bowl- 
 ders, but wherever the streets have cut down into the soil 
 they show, at the depth of a few feet, an uustratiiied deposit 
 abounding in striated stones. Superimposed upon this ridge 
 there is a thin stratified deposit of varying depth, but in- 
 creasing in extent down the slope toward tide-water. 
 
 At Port Townsend, on the Strait of Juan de Fuca, and 
 forty miles northwest of Seattle, the coarsely stratified de- 
 posit is niuch greater in extent. A noteworthy section of 
 this I had the privilege of studying at Point Wilson, two 
 miles and a half northwest of Port Townsend. Here, facing 
 
 
 Fig. 60.— Section of the deposit at Point Wilson described in the text, showing one hnn- 
 dred and fifty feet in height, about one hnndred of which is coarsely stratified, and 
 contains layers of vegetable matter. Bowlders from till at the top have fallen down 
 to form a tains at the water^s edge. 
 
 the strait toward the north, is a perpendicular bluff from one 
 hnndred and fifty to two hundred feet in height, composed 
 
BOUNDARY OF THE GLACIATED ABEA. 183 
 
 of material eoarselj stratified throughout its lower portion, 
 but capped at the summit by about forty feet of coarse, un- 
 stratified material abounding in large striated bowlders, which, 
 as they have been washed out by the erosion of the sea, are 
 falling down to the foot of the bluff in ijnmense numbers. 
 Near the bottom of the bluff there are several strata of vege- 
 tal deposits. One of these, two feet thick, consisted almost 
 wholly of the fragments of the bark of the fir-trees which 
 are now so characteristic of that region. Fragments of wood 
 project from the freshly exposed bank in great abundance. 
 The meaning of these facts will be more readily apparent 
 after a study of the phenomena to the north of the strait. 
 
 The Strait of Juan de Fuca is from fifteen to twenty 
 miles in width, setting in from the Pacific Ocean and run- 
 ning east and west. Its north shore, near Victoria, on Van- 
 couver Island, is remarkably clear of glacial debris. The 
 rocks, however, near Victoria, exhibit some of the most re- 
 markable effects of glacial scoring and striation anywhere to 
 be found. Immediately south of Victoria long parallel fur- 
 rows rise from the shore of the inlet, and ascend the slope 
 of the hill to the south to its summit, a hundred feet or more 
 above the water-level. At the steamboat-landing, outside of 
 the harbor, extensive surfaces freshly uncovered exhibit the 
 movtorvnse appearance of true glaciation, and, in addition to 
 the finer and abundant scratching and striae, display numer- 
 ous glacial furrows from six inches to two feet in depth, 
 from twenty to thii'ty-two inches in width, and many feet 
 in length. These grooves are finely polished and striated, 
 resembhng those with which geologists are familiar on the 
 islands near the the western end of Lake Erie. Like the 
 corresponding grooves on the islands of Lake Erie, some of 
 those near Victoria also form graceful curves, adjusting them- 
 selves to the retreating face of the rock-wall. That the mo- 
 tion of the ice at Victoria was to the south appears not only 
 from the direction of the striae, but from the fact that the 
 stoss sides of the glaciated rocky projections are toward the 
 north. That they are due to glacial action, and not to ice- 
 
184 THE ICE AGE IX NORTH AMERICA. 
 
 Fig. 61.-GliKial groovings near the landing at Victoria <rw tcxtl. (From Pliotograpli.) 
 
 bergs, is evident l)oth from tlieir character and from their 
 analogy to numerous phenomena farther to the north vin- 
 qiiestionably connecteil with true glaciers. 
 
BOUiTDABY OF THE OLACIATED AREA. 185 
 
 Speaking of Vancouver Island and the adjacent region, 
 the Scotch geologist, Robert Brown, uses the following lan- 
 guage: 
 
 The chief rock in situ there is a dense, hard, feldspathic 
 trap, and this is plowed in many places into furrows six to 
 eight inches deep and from six to eighteen inches wide. The 
 ice-action is also well shown in the sharp peaks of the erupted, 
 intruded rocks, having been broken off and the surface smoothed 
 and polished, as well as grooved and furrowed, by the ice-action 
 on a sinking land, giving to the numerous promontories and 
 outlying islands which here stud the coast the appearance of 
 rounded bosses, between which the soil is found to be composed 
 of sedimentary alluvial deposits, containing the debris of ter- 
 tiary and recent shelly beaches, which have, after a period of 
 depression, been again elevated to form dry land, and to give 
 the present aspect to the physical geography of Vancouver 
 Island. 
 
 The whole surface of the country is strewn with erratic 
 bowlders. Great masses of sixty to one hundred tons in weight 
 — chiefly of various igneous and crystalline as well as sedi- 
 mentary rocks, sufficiently hard to bear transportation — are 
 found scattered everywhere over the island from north to south, 
 and through the region lying on the western slope of the Cas- 
 cade Mountains.* 
 
 The same observer thus speaks of the glacial phenomena 
 on the mainland in the same vicinity : 
 
 The following section is given to show the general character 
 of the drift at Esquimault Harbor : 
 
 Black sandy and peaty ground, with broken shells 2 to 6 feet. 
 
 Yellowish sandy clay, with casts of shells (Oardium and 
 
 Mya) and a few pebbles and bowlders 6 to 8 " 
 
 Gravel of scratched pebbles resting on rock 2 to 3 " 
 
 The rocks are grooved and scratched at the junction ; the 
 direction of the glacial markings is between north to south 
 and north -north west to south-southeast. In a well-sinking, at 
 
 * "American Journal of Science," vol. c, 1870, pp. 320, 321. 
 
186 THE IGE AGE IN NORTH AMERICA. 
 
 Esquimanlt Barracks (for the boundary commission), the lower 
 gravel was reached at forty-two feet, after going through a 
 sandy-blue clay without shells or bowlders. The section in the 
 cliff between Albert Head and Esquimanlt is as follows : 
 
 Blue drift clay, with bowlders; junction with rock 
 
 not seen 70 feet. 
 
 Fine sand and gravel, passing upward into coarse 
 
 quartzose gi-avel 100 to 120 feet.* 
 
 I saw at Seaborne (near Bellingham Bay), in the cuttings 
 made for a tramway, the finest instances of fluting and groov- 
 ing — evidences of glacial action — that I have ever seen on this 
 coast. They were ninety feet in length, running north and 
 south, according to the theory of Professor Agassiz. f 
 
 Vancouver Island, which trends parallel with the shore 
 of the continent northwest by southeast, is nearly three hun- 
 dred miles in length and from fifty to seventy-five in breadth. 
 In character it seems but a continuation of the Coast Range 
 of mountains, with numerous peaks rising from four to seven 
 thousand feet above the sea. The shore-line of the continent 
 upon the northeastern side of the Strait of Georgia is formed 
 by a continuation of the Cascade Range, with a general ele- 
 vation of from three to eight thousand feet, and is penetrated 
 in numerous places, to a distance of from twenty-five to 
 seventy-five miles, by inlets or fiords some miles in width. 
 Dr. George M. Dawson describes the glacial phenomena in 
 Bute Inlet (which enters the Strait of Georgia about oppo- 
 site the center of Vancouver Island, in latitude 50° 30') in 
 the following language : 
 
 This chasm, forty miles in length, and running into the 
 center of the Coast Range, is surrounded by mountains, which 
 in some places rise from its borders in cliffs and rocky slopes 
 to a height of from six to eight thousand feet. It must have 
 been one of the many tributaries of the great glacier of the 
 Strait of Georgia, and accordingly shows evidence of powerful 
 
 * " Quarterly Journal of London Geological Society," 1860, p. 202. 
 f " American Journal of Science," vol. c, pp. 322, .S2.3. 
 
BOUNDARY OF THE GLACIATED AREA. 187 
 
 ice-action. The islands about its mouth are roches moutonnees, 
 polished and ground wherever the original surface has been 
 preserved. In Sutil Passage, near its entrance, grooving ap- 
 pears to run about south 30° west. A precipitous mountain 
 on Valdez Island, opposite Stuart Island, and directly blocking 
 the mouth of the inlet, though 3,013 -feet high, has been 
 smoothed to its summit on the north side, while rough toward 
 the south. The mountain-side above Arran Passage shows 
 smooth and glistening surfaces at least two thousand feet up 
 its face ; and, in general, all the mountains surrounding the 
 fiord present the appearance of having been heavily glaciated, 
 with the exception of from one to two thousand feet of the 
 highest peaks. The high summits are rugged and pointed, 
 and may either never have been covered by glacier-ice, or owe 
 their different appearance to more prolonged weathering since 
 its disappearance. In some places parallel flutings high up 
 the mountain-sides evidence the action of the glacier, while in 
 others it is only attested by the general form of the slopes, or 
 detected under certain effects of light and shade. ... At the 
 mouth of the Howathco Eiver, discharging into the head of 
 Bute Inlet, striation shows a direction of movement south 33° 
 east ; but in every case the motion appears to have been di- 
 rectly down the valley, and to have conformed to its changes 
 in course. Glacier.-ice may still be seen shining bluely from 
 some of the higher valleys at the head of the inlet, and farther 
 up the Howathco River there are many glaciers in lateral val- 
 leys, some of which descend almost to the river-level. 
 
 Mr. James Richardson, who has had an opportunity of 
 examining many of the inlets north of Vancouver Island, 
 writes as follows :* "Throughout the whole of the inlets and 
 channels which were examined, wherever the surface of the 
 rock is exposed, the ice-grooving and scratching are very con- 
 spicuous, from mere scratches to channels often several feet 
 in width, and from a few inches to as much as two or three 
 feet in depth. Often they can be distinctly seen with the 
 naked eye from the surface of the water to upward of three 
 thousand feet above it on the sides of the mountains. They 
 
 * " Beport of Progress of the Geological Survey of Canada, 1874-"76," p. 8. 
 
188 TEE ICE AGE IN NORTE AMERICA. 
 
 run in more or less parallel lines, and are not always horizontal, 
 but deviate slightly up or down. " * 
 
 Mr. Robert Brown, whom we have already quoted, gives 
 the following additional information as to regions still far- 
 ther north : 
 
 I have not been in Alaska proper, but in 1866, in a visit to 
 the Queen Charlotte Islands, lying some thirty or forty miles 
 off the northern coast of British Columbia, close to the southern 
 boundary of the former Territory, marks of the northern drift 
 quite as marked as in Vancouver Island were found there. f 
 
 As already indicated, the mountains on either side the 
 Strait of Georgia, and northwestward to the head of Lynn 
 Canal, about latitude 59° 20', are snow-clad throughout the 
 whole season. The shores are everywhere rocky and pre- 
 cipitous, retaining in many places far up their sides glacial 
 striae parallel with the direction of the numerous channels 
 which thread their way through the Alexander Archipelago. 
 I had opportunity at Loring, on the western shore of KevUla 
 Gigedo Island, to examine minutely the striation on the stores 
 and islands of Naha Bay. There are now no glaciers coming 
 down from the mountains of this island, but the shores and 
 islands abound in well-preserved glacial striae running west 
 by 18° north, corresponding to the direction of the local val- 
 ley, down which a glacier came in former times, entering 
 Behm's Canal nearly at right angles to its course upon that 
 side of the island. This is about latitude 55° 40'. 
 
 Upon proceeding one degree to the north, I liad oppor- 
 tunity also to observe closely the striae at Fort Wrangel. 
 Here, too, they show the influence of the continental eleva- 
 tion to the east, and are moving outward in a westerly direc- 
 tion toward the Duke of Clarence Strait. 
 
 In Glacier Bay the evidence of the recent vast extension 
 of the glaciers down the bay, and of the facility with which 
 
 * " On the Superficial Geology of British Columbia," in the " Quarterly Jour> 
 nal of the Geolo^cal Society," vol. xxxiv, February, 1878, pp. 99, 100. 
 f " American Journal of Science," vol. c, p. 323. 
 
BOUNDARY OF TEE GLACIATED AREA. igQ 
 
 glacial ice adjusts itself to the local topography, is, as already 
 stated, of a most explicit character.* In addition to the evi- 
 dence already mentioned, we may add that numerous islands 
 project from the surface of the Muir Glacier, as from the 
 waters of an archipelago, and that the summits of these bear 
 every mark of having been freshly uncovered by the decreas- 
 ing volume of ice. Also that below the mouth of the gla- 
 cier numerous islands in the bay present exactly the same ap- 
 pearance, except that they now project from water instead of 
 ice. Their recent glaciation is indicated by every character- 
 istic sign. Willoughby Island, about the middle of the bay, 
 is as much as a thousand feet above the water. Were the ice 
 to retreat a few miles farther back from its present front, it 
 would doubtless uncover an extension of the bay, with numer- 
 ous islands similar to those now dotting its surface south of 
 the glacier. Fresh glacial debris lingers on the flanks of the 
 mountains on either side of the inlet, to a height of 2,000 
 feet. The fact is also worth repeating and emphasizing that 
 at 3,700 feet above tide striae were observed, on the east side 
 of Muir Inlet, not pointing down the mountain, as might be 
 expected, but parallel with the axis of the bay, showing, be- 
 yond controversy, that the present glacier is but a remnant 
 of an earher ice-movement, similar in character and direction 
 to the present, but of vastly greater dimensions, and which 
 extended until it filled the whole bay to its mouth in Cross 
 Sound, a distance of twenty-five miles. At Sitka, also, the 
 rocks of the harbor are all freshly striated — the direction of 
 the striae being toward the west — ^thatis, toward the open sea. 
 Glaciers still linger in the mountains at the head of the bay 
 to the east of Sitka. 
 
 The absence of glacial phenomena north of the range of 
 mountains, which forms the southern boimdary of Alaska, and 
 over the adjacent plains of Northern Siberia, completely 
 disproves the once current theory that the glacial period 
 was characterized by a vast ice-cap extending in all directions 
 
 * See above, p. 56 et seq. 
 
190 THE ICE AGE IN NORTH AMERICA. 
 
 from the pole. For, in both these regions, though the soil 
 is frozen to a depth of several hundred feet, there are no indi- 
 cations of the presence of moving ice. Stagnant ice, however, 
 in many places takes the place of ordinary rocks. The expedi- 
 tion of Dawson to the Yukon in 1887 and that of Schwatka 
 and Hayes around Mt. St. Elias in 1892 demonstrated an 
 actual northward movement of ice. Dawson writes: 
 
 In the Lewes and Pelly Valleys, traces of the movement of 
 heavy glacier-ice in northward or nortl)westward directions, 
 were observed in a number of cases, the grooving and furrow- 
 ing being equally well marked at the water-level and aci-oss 
 the summits of hills several hundred feet higher. The facts 
 are such as to lead to the belief that a more or less completely 
 confluent glacier-mass moved in a general northwesterly direc- 
 tion, from the mountainous districts south of the southern 
 sources of the Yukon, toward the less elevated country which 
 borders the lower river within the limits of Alaska. This ob- 
 servation, taken in connection with the evidence of the former 
 northward movement of glacier-ice in the arctic regions to the 
 east of the Mackenzie, appears to have very important bear- 
 ings on theories of general glaciation.f 
 
 From all these facts it seems evident that the supposition 
 of a slight intensification of the present conditions so favor- 
 able to the production of glaciers in southeastern Alaska, 
 unravels the whole intricate web of glacial phenomena upon 
 the western coast of North America. 
 
 The present formation of glaciers on the coast of south- 
 eastern Alaska is favored not so much by the coolness of the 
 climate as by the elevation of the mountains and the excess- 
 ive amount of precipitation, which, as before stated, is not 
 far from one hundred inches annually. There is no evidence 
 that the elevation of the coast has materially changed in 
 recent times. But it would require only a slight change in 
 the amount of precipitation, or a slight diminution of tem- 
 
 * "Science," vol. xi, 1888, p. 186; "Geological Magazine," vol. Ixx, 
 p. 347 et seq. 
 
 t "Annual Report of the Geological Survey," 1886, p. 56, R. 
 
BOUNDARY OF THE GLACIATED AREA. 
 
 191 
 
 perature, to secure all the additional force required to extend 
 the present glaciers of southeastern Alaska, British Columbia, 
 
 Fio. 82.— Map of area covered by the North American ice sheet of the Pleistocene epoch 
 at its maximum extension, showing the approximate southern limit of glaclatlon, 
 the three main centers of Ice accumulation, and the drlftless area within the glacia- 
 ted region. It Is now proven that the maximum advance from the Keewatln center 
 preceded that from Labrador;sIncebowldery deposltsfromthenortheastextend 
 over those from the northwest throughout a large part of Indiana and Illinois and 
 for quite a distance 1 nto Iowa. Lake Superior copper Is found 1 n the oldest deposits 
 In Pennsylvania, while red Jasper conglomerate bowlders from Lake Huron are 
 foimd in the newer deposfts west of the Mississippi a few miles from Keokuk. 
 (From the United States Geological Survey.) 
 
 and of the Cascade Range of State of Washington and Ore- 
 gon, until they should gorge all the channels of the Alex- 
 
192 TEE IGE AOE IN NORTE AMERICA. 
 
 ander Archipelago, fill the space occupied by the Strait of 
 Georgia between Yancouver Island and the mainland, and 
 cover with ice the whole valley between Mount Tacoma and 
 the Olympian Mountains, where now we find the vast mo- 
 raine deposits of the islands and shores of Puget Sound. 
 
 A simple calculation impresses one with a sense of the 
 unstable equilibrium of the forces leading to the increase or 
 diminution of a glacier. We estimated that 77,000,000,000 
 cubic feet of ice annually pass through the gorge at the head 
 of Muir Inlet, and that the area of the ice-field supplying 
 this stream is about twelve hundred square miles. The total 
 amount of ice entering the inlet, therefore, is only equivalent 
 to about two feet of ice over the field of supply. If from 
 any cause two feet more of ice should annually accumulate 
 over this area, or two feet less should annually melt away, 
 the amount of ice compelled to go through the gorge would 
 be doubled, and this would doubtless fill up the whole inlet 
 and bay to the south. When we reflect that, according to 
 Newcomb,* the average amount of ice which would be 
 melted by the sun over the whole earth is something more 
 than a hundred feet a year, and that, therefore, a change in 
 intensity amounting to only one fiftieth of that exhibited 
 by the present meteorological forces would produce the re- 
 sults just mentioned, we can readily believe that oscillations 
 in such a great glacier may be frequent in occurrence and of 
 great magnitude. 
 
 Southward, in Oregon, the Willamette Valley was filled 
 in a similar manner by an extension of the glaciers still lin- 
 gering on the flanks of Mounts Hood and Shasta. The 
 absence of drift on the southern shore of Vancouver Island 
 seems to point to a termination of the southerly movement 
 from Alaska in the Strait of Juan de Fuca, where perhaps 
 the confluent streams turned westward, and sent off vast 
 drift-laden icebergs to the sea. Mount Baker, immediately 
 to the east of this point, upward of ten thousand feet high, 
 
 * " Popular Astronomy," p. 247. 
 
BOUNDARY OF THE QLACIATEB AREA. 193 
 
 and still preserving glaciers on its flanks, would have lent 
 material aid in this seaward movement. The shores and 
 islands about Puget Sound have the appearance of being the 
 terminal deposits of confluent glaciers coming down from 
 the flanks of Tacoma on the southeast, and from the lower 
 portions of the Cascade Range farther north, joined by 
 smaller glaciers from the Coast Range on the west. It is 
 clear that the earlier glacial movements on the Pacific coast 
 were local in character, and must be studied independently 
 of those east of the Rocky Mountains, and can be imderstood 
 only by reference to the glaciers which still linger at the head 
 of all its numerous valleys, inlets, and fiords. In these the 
 investigator has a vera causa ever before his eyes to guide 
 his steps and to assist his imagination. 
 
CHAPTER VIII. 
 
 DEPTH OF THE ICE DDKING THE GLACIAL PEEIOD. 
 
 Thebe are two sources of information concerning the 
 depth attained by the ice in North America during the Gla- 
 cial period : First, we have direct evidence in the height of 
 the mountains which have marks of glaciation upon their 
 summits ; secondly, calculations can be made, with some 
 approximation to truth, from the distance through which 
 bowlders have been transported. 
 
 Very conveniently for the glacialist, the mountains of 
 New England and the Middle States serve the purpose of 
 glaciometers, preserving upon their flanks and summits in- 
 dubitable evidence of the great depth of the ancient ice-sheet 
 over that portion of the country. 
 
 It requires but a cursory examination to see that the 
 highest point of Mount Desert Island, on the coast of Maine, 
 was completely covered by the glacier, showing that at the 
 very margin of the ocean the ice must have been consider- 
 ably more than 1,500 feet deep. Even Mount Washington, 
 in New Hampshire, was either wholly enveloped by the ice- 
 current, or if a pinnacle projected above the glacier it could 
 have been no more than 300 or 400 feet higher. Professor 
 Hitchcock having found transported bowlders to within that 
 distance of the summit. The ice-current passed over the 
 Green Mountains where they are from 3,000 to 5,000 feet in 
 height in a course diagonal to that of their general direction, 
 showing that such a mountain-chain made scarcely more of a 
 ripple in the moving mass than a sunken log would make in 
 a shallow river. Farther south. Mounts Monadnock, Tom, 
 
DEPTH OF THE ICE DUMNG THE GLACIAL PERIOD. 195 
 
 and Holyoke, the Berkshire Hills, and East and West Mount- 
 ain, near New Haven, were also completely enveloped in ice. 
 Between the Adirondacks and the Alleghanies the Mohawk 
 Valley was filled nearly to the height of the Catskills, and the 
 southern edge was pushed up in Monroe, Sullivan, Tioga, 
 and Potter counties. Pa., to a height of 2,000 or 2,600 feet 
 above the sea. 
 
 In remarking upon the accompanying sections, Professor 
 Lesley, who made them, says that while they do not satisfy 
 him in several important particulars, such as the regularity 
 of its surfape, the location of possible crevasses, the descent 
 into the plain, the distribution of bowlders, etc., they serve 
 to give a correct generalized view — first, of the great thick- 
 ness of the ice-sheet, by contrasting it with the sections of the 
 solid rocks from the present surface down to the plane of 
 sea-level ; second, to allow the reader to judge for himself of 
 the extent of the eroding power at this point. We append 
 Professor Lesley's reasons for constructing the scale as he has : 
 
 As to the first point, I have given to the surface of the ice 
 a gentle slope southward, by making it 600 feet thick over the 
 mountain, and 1,800 feet thick over Cherry Creek ; which 
 slope, if, continued northward, would suffice to make the ice 
 cover the highlands (2,000 feet above tide) farther north, as we 
 know that it did. Thirty years ago Agassiz gave me his law of 
 the necessary minimum thichness of a glacier for crossing a 
 barrier. It was in a conversation immediately subsequent to 
 his study of the striae on the top of Mount Desert, pointing 
 from Mount Katahdin, and descending into the sea. He said 
 that no- glacier could cross a ridge unless its thickness at the 
 summit of the ridge was at least one half the height of the 
 ridge. By this rule he judged that the ice-sheet of Maine was 
 750 feet thiok over the top of Mount Desert ; and this would 
 account for the great distance south of Mount Desert of the 
 terminal moraine. 
 
 This rule was obtained by Agassiz and Desor in their long 
 residence on the glacier of the Aar, and was based on numerous 
 observations of local Alpine glaciers where they were crevassed 
 
DEPTH OF THE lOE DURING THE GLACIAL PERIOD. 197 
 
 in surmounting barriers of rock. Whether it is a rule to hold 
 good under quite different circumstances, in the case of conti- 
 nental ice-sheets, or not, we have no means of knowing ; but 
 it is the only rule at our command. I have applied it to the 
 case of the Kittatinny Mountain, and made the ice-sheet 600 
 feet thick where it crossed the crest. It may have been any 
 amount thicker for all we know. 
 
 The two sections given in this plate were constructed by 
 H. M. Chance, some years ago, after special topographical 
 surveys and contour-line maps had been made by him at the 
 Delaware, Lehigh, and Schuylkill Water-Gaps. They are pub- 
 lished in Eeports G* and D', with the maps to which they 
 belong. 
 
 I have added to the north end of the upper section one of 
 the transverse sections of Godfrey's Ridge, south of Strouds- 
 burg, which I made in 1840, in order to show the outcrops of 
 Oriskauy sandstone and Lower Helderbei-g limestone from 
 which the bowlders were taken by the ice which now lie on the 
 Kittatinny Mountain. 
 
 Mr. Lewis remarks, on page 91, that "almost every block 
 of limestone that was taken from the Helderberg Ridge in 
 Cherry Valley can be traced to its destination " ; and on page 
 88 he directs special attention to the large numbers and great 
 sizes of them which were carried across Cherry Valley and left 
 perched upon the top of Red Ridge overlooking Wolf Hollow ; 
 and to one which he found on the very summit of the Kitta- 
 tinny Mountain, at an elevation of 1,200 feet above the out- 
 crop in Godfrey's Ridge.* 
 
 In the earlier reports upon the mountain-region of north- 
 eastern Pennsylvania, it vras concluded by Professors I. C. 
 White and H. C. Lewis that the ice in that part of the State 
 had not surmounted elevations more than 2,220 feet above 
 tide. But Professor J. C. Branner, on re-examining the 
 region in the summer of 1886, found distinct glacial marks 
 upon the summit of Elk Mountain, in Susquehanna county, 
 2,700 feet above tide ; while the whole range of Lackawanna 
 
 ' " Second Geological Survey of Pennsylyania,'' vol. Z, p. xiv. 
 
198 THE ICE AGE IN NORTE AMERICA. 
 
 Mountains, northeast of the Susquehanna Gap at Pittston, 
 showed distinct signs of glaciation on their liigliest summits, 
 which are from 2,000 to 2,200 feet above tide. This would 
 give a depth of 1,500 feet in the Susquehanna Valley in that 
 neighborhood.* 
 
 The most formal attempt to estimate from known data 
 <iie depth of the ice near its ancient margin is that by Pro- 
 fessor J. C. Smock, in a paper f before the American Asso- 
 ciation for the Advancement of Science at Montreal. Pro- 
 I'^ssor Smock finds definite evidence in northern New Jersey 
 of a depth of only about seven hundred feet to the ice, 
 though it is impossible to say that it was not more. For ex- 
 ample, the highest points of Schooley's Mountain table-land 
 consist of moraine hills from twelve to thirteen bundred feet 
 above tide, while the Musconetcong Yalley to the west, which 
 the ice had to fill before it surmounted the elevations indi- 
 cated, is seven hundred feet lower, showing that the ice must 
 at that point have been in the neighborhood of a thousand 
 feet in thickness. Professor Smock was also the first one to 
 ascertain that Pocono Mountain, in Monroe county. Pa., 
 showed signs of glaciation up to a height of over two thou- 
 sand feet. From the study of the glacial phenomena of tbat 
 region. Professor Smock correctly infers that " the inclination 
 of the continental ice-sheet of the Glacial epoch was not uni- 
 form. The rise was probably steep near the margin. . . . 
 Thus, near Feltville and Summit, the drift-covered Spring- 
 field Mountain, which is about a mile north of the line, is 
 nearly six hundred feet high. The high drift-hills near 
 Mount Hope (960 feet) [also] show a great thickness near 
 the margin. . . . Northward the angle of the slope dimin- 
 ished, and the glacier surface approximated to a great level 
 plain. The distance between the high southwestern peaks 
 of the Oatskills and Pocono Knob in Pennsylvania is sixty 
 
 * " The Thickness of the Ice in Northeastern Pennsylvania during the Gla- 
 cial Epoch," by J, C. Branner, in the " American Journal of Science," vol. cxxxii, 
 1886, pp. 362-366. 
 
 f "American Journal of Science," vol. cxxv, 1883, p. 339 et seg. 
 
DEPTH OF THE ICE DURING THE GLACIAL PERIOD. 199 
 
 miles. The difference in the elevation of the glacier could 
 not have exceeded a thousand feet. In that direction the 
 slope was less than on a meridian line from the Catskills 
 southward." 
 
 Professor Dana estimates that the height of the ice 
 " above the region of New Haven, in soathem Connecticut, 
 may have exceeded two thousand feet, and could hardly have 
 been less than fifteen hundred." 
 
 So far the evidence is direct and positive, because the 
 glacial marks are left upon the mountain-summits mentioned. 
 How far still above these summits it rose is not so easily 
 determined. From this amount of direct evidence it may 
 also reasonably be inferred that the depth of the ice over the 
 lake and prairie region of the West was equally great. If 
 our interpretation of the facts implying the presence of an 
 ice-sheet in North America is correct, we have also positive 
 evidence of a great depth of ice over the central portion of 
 British America between Hudson Bay and the Rocky Mount- 
 ains. Here we find, according to Dawson, that bowlders 
 from the Laurentian axis of the continent, which stretches 
 from Lake Superior northward to the west of Hudson Bay, 
 have been transported westward a distance of seven hundred 
 miles, and left upon the flanks of the Rocky Mountains at 
 an elevation of something over four thousand feet.* But 
 nowhere does the Laurentian axis reach two thousand feet, 
 its average elevation, according to Sir William Logan, being 
 from fifteen to sixteen hundred feet. If these bowlders 
 were, as we suppose, transported by glacial ice, then the ice 
 must have accumulated over the Laurentian axis to a depth 
 of 2,400 or 2,500 feet, and must have been several hundred 
 feet deeper in the central part of the Red River Valley. 
 Mr. R. G. McConnell, of the Canadian Survey, also, from 
 more direct evidence, estimates f that, in the plains surround- 
 ing the Cypress HUls (in the upper valley of the South 
 Saskatchewan, in latitude 49° 30', longitude 110°, and not 
 
 * See p. 214. f See his " Report on the Cypress Hills Wood Mountain." 
 
200 THE ICE AGE IN NORTH AMERICA. 
 
 more than one hundred miles from the southwestern limit 
 of the glaciated area in Montana), the continental glacier, or 
 the glacial sea, according to which one of the theories of 
 transportation is adopted, had a maximum depth of two 
 thousand feet. This he determines by the height to which 
 he found glacial deposits resting upon the Cypress Hills. It 
 is the necessity of accounting for such an elevation of bowl- 
 ders in glacier-ice which has made the Canadian geologists 
 hesitate about accepting the glacial theory. It seemed to them 
 at first more probable that there had been a depression of 
 about four thousand feet in the Rocky Mountain region, and 
 that these bowlders were transported from the Laurentian 
 axis by floating ice. We think, however, that such facts as 
 are illustrated in the diagram of Professor Lesley's on page 
 196, as well as other facts yet to be stated concerning the 
 elevation of bowlders in ice, go far to remove the objections 
 to the glacial theory urged by the Canadian geologists, and 
 we therefore speak with considerable confidence of the great 
 depth of the ice over the Laurentian axis. The glacial the- 
 ory, moreover, as Dr. Dawson frankly and early admitted, 
 relieves them of many difficulties in accounting for the 
 noticeable absence of other indications of subsidence in the 
 region under consideration. For example, there is, first, ac- 
 cording to Dr. Dawson,* a complete absence of any marine 
 animal remains in the drift over that region ; and, secondly, 
 " the yielding, scarcely solidified " sediments over this vast 
 region bear slight evidence of any such great change in ele- 
 vation. 
 
 The great depth of the ice over the lake-region during 
 the Glacial period is also evident from the second mode of 
 calculation, namely, that based upon the distance over which 
 bowlders are known to have been transported by the direct 
 movement of the ice. The fluidity and plasticity of ice are so 
 slight that, where we find it moving hundreds of miles over 
 a level country, the thickness at the starting-point can scarcely 
 
 " Report on the Forty-ninth Parallel," as above, pp. 216, 244, 260, et al. 
 
DEPTH OP THE IGE DUBINO THE GLACIAL PERIOD. 201 
 
 have been less than that indicated by the evidence in New 
 England. Over southern Ontario and Michigan, and over 
 the larger part of Wisconsin, Minnesota, northern Illinois, 
 and Iowa, the ice must have been thousands of feet in depth, 
 or it never could have pushed southward to the latitude of 
 Cincinnati, Louisville, and St. Louis. 
 
 The uncertainties attending this mode of calculation are, 
 however, very great, and it can be taken only for approxi- 
 mate results. In the Alps the lowest mean slopes down 
 which glaciers move are 2^° to 3°, or about 250 feet to the 
 mile. But, as Professor Dana notes,* the thickness of the 
 ice there is not over 500 feet. Mathematicians are not able 
 to deal successfully with the problems of friction in viscous 
 bodies. How such a body will behave in greatly increased 
 masses can be determined only by experiment. In Green- 
 land, where the thickness of the ice more nearly approaches 
 that of the ice-sheet formerly covering the northern part of 
 the United States, Jensen fonnd the slope of the Frederik- 
 shaab Glacier to be 0° 49', or about seventy-dve feet a mile ; 
 while Holland found the slope of the Jakobshavn Glacier to 
 be only 0° 26', or about forty-five feet to the mile.f This 
 latter slo'pe of the surface of the continental glacier would, 
 if continuous, make the thickness of the ice 10,000 feet over 
 northern New England, and about 11,000 feet over Lake 
 Erie, while the' depth of the ice in this calculation over the 
 region north of Lake Huron and Lake Superior, from which 
 certain bowlders in Kentucky came, would be nearly 30,000 
 feet, since the distance moved is 600 miles or more. 
 
 Upon the supposition that the slope from the front to- 
 ward the interior was but half a degree, Croll estimates that 
 the depth of ice at the south pole, at the center of the Ant- 
 arctic Continent, must be as much as twelve miles. This is 
 on the supposition that the diameter of the continent is 2,800 
 miles. The same rate of calculation would, according to 
 
 * " American Journal of Science," vol. cxxvi, 1883, p. 348. 
 f " Meddelels'er cm Gronland," 1879, and "American Journal of Science," 
 vol. cxxiii, 1882. p. 364. 
 
202 THE ICE AGE IN NORTH AMERICA. 
 
 Hitchcock,* require the ice of the Glacial period to be eight 
 miles deep over the central part of Labrador; and, if the 
 movement came from Greenland, the same slope of forty- 
 five feet to the mile would reach, at that point, the astonish- 
 ing depth of eighteen miles. 
 
 It is not necessary, however, to suppose a uniform slope 
 to the center of so vast an ice field. If, however, we assume 
 with Chamberlin and Salisbury,t that there was an actual 
 movement of glacial ice of 1,600 miles from the Labradorian 
 center to the southern part of Illinois, and of equal extent 
 from the Keewatin center west of Hudson's Bay to Topeka, 
 Kansas, an average slope of but tenfeet to themilewouldgive 
 a depth of three miles at the centers. That the depth was as 
 great as this, seems the more probable from the fact that the 
 Keewatin center is low, and unless the elevation of that 
 region was then much greater than it is now the movement 
 must have been produced by the pressure caused by the simple 
 accumulation of ice. Staggering to the imagination as these 
 suppositions are, they seem to be inevitable inferences from 
 the established facts. A depth of three miles over the central 
 portions of the glaciated area in North America is, therefore, 
 by no means improbable. 
 
 * "New Hampshire Geological Report," vol. iii, pp. 320, 321. 
 t Geology, vol. iii, pp. 330, 357. 
 
CHAPTEE IX. 
 
 TBEMINAL MOEAINES. 
 
 Since the word moraine originally designates a consider- 
 able accumulation of glacial debris, it has been fonnd impos- 
 sible to apply the term to the marginal deposits along the 
 whole boundary ; for, as was stated in the chapter treating 
 of the subject, the glacial margin in the Mississippi Valley is 
 not marked by such accumulations as characterize it east of 
 the Alleghanies. The glacial deposits south of New England 
 are, however, truly phenomenal in their extent, and can with 
 perfect propriety be called terminal moraines. Why glacial 
 debris should have accumulated to such an extent along that 
 line it is impossible to tell with certainty ; but, recurring to 
 the principles already presented, it would seem, not only that 
 such an extensive terminal moraine indicates an abundance 
 of easily disintegrated rock to the north offering itself for 
 transportation in tlie line of the glacial movement, but that 
 it also indicates that the ice-front remained for a long time 
 stationary in the latitude of New York between Nantucket 
 and the Delaware River. How much the proximity of the 
 ocean may have had to do with the maintenance of this sta- 
 tionary ice-front we may never fully determine ; but, both 
 by its natural effect in eroding the advancing ice-column, 
 and thus limiting its movement, and by its tendency to pro- 
 vide moisture to the clouds which furnished the glacier of 
 that whole region with its fresh supply of snow, the neigh- 
 boring waters of the Atlantic would seem to be an adequate 
 cause for the phenomenon. At any rate, in the hills of Cape 
 Cod, of Nantucket, of Martha's Vineyard, of the Elizabeth 
 
204 TEE WE AGE IN NORTH AMERICA. 
 
 Islands, and of the south shore of Khode Island, and in those 
 forming the backbone of Long Island, we have one of the 
 most remarkable true terminal moraines anywhere to be 
 found in the world. 
 
 Throughout their whole extent these terminal accumula- 
 tions form a marked feature in the landscape, rising for a 
 considerable portion of the distance from one hundred and 
 fifty to three hundred feet above the general level of the 
 country, and being dotted over with huge bowlders transport- 
 ed a greater or less distance from the north. Kettle-holes 
 and the small lakelets which they inclose are also constant 
 features in the landscape. Throughout this whole extent, 
 also, the moraines are flanked on the south by extensive de- 
 posits of the " over-wash " gravel carried out by the water 
 arising from the melting ice. The line of these moraines is, 
 of course, at right angles to the direction of the ice-movement 
 which terminated here. 
 
 It is a remarkable confirmation of the theory already pre- 
 sented in explanation of kettle-holes, that a study of those 
 which mark the moraines of this region reveals a strong tend- 
 ency in them to arrange themselves with their longer diameters 
 parallel to the general trend of the moraine. Professor B. F. 
 Koons * has taken the exact bearings of one hundred and six 
 of these kettle-holes upon the island of Naushon and upon the 
 mainland from Wood's Holl to Falmouth, and finds that the 
 longer axis of eigh.ty-two out of that number is approximately 
 parallel to the direction of the moraine — that is, nearly at right 
 angles to the direction of the ice-movement ; and he is doubt- 
 less correct in his inference that " this is what we should ex- 
 pect if the kettle-holes marked the localities where fragments 
 of ice were broken off from the face of the glacier and buried, 
 wholly or in part, by the earth and stones borne down by 
 the ice-sheet." By reference to the chapter upon the Muir 
 Glacier, with the illustration there introduced, the reader may 
 
 * " American Journal of Science," vol. cxxvii, 1884, p. 260 el seg. ; vol. 
 cxlix, 1885, p. 480 d seq. 
 
TERMINAL MORAINES. 
 
 205 
 
 easily convince him- 
 self of the correct- 
 ness of this sugges- 
 tion. " Some of 
 these kettle - holes," 
 Professor Koons 
 goes on to say, "are 
 upon a truly grand 
 scale ; for example, 
 one which contains 
 several smaller, with- 
 in the large depres- 
 sion, and is like an 
 immense amphithea- 
 tre with the hills ris- 
 ing upon every side 
 of it. Its highest 
 border is one hun- 
 dred and fifty feet 
 above the bottom and 
 the outlet is forty 
 feet above the small 
 lake at its center ; 
 and on the south side, 
 near its border, but 
 upon still higher 
 ground, a bowlder 
 stands projected 
 against the southern 
 sky like a huge sen- 
 tinel as the observer 
 views it from the 
 bottom of this im- 
 mense pit." * As 
 
 * " American Journal of 
 Science," vol. cxxvii, p. 262. 
 
 m 'O 
 
 S0O3 S 
 QU .id 
 
 -OJfi 
 
 
 ■atSS 
 3 >. 
 bT eft's 
 
 a Sis 
 
 OS w o 
 
 Sfe'H 
 
 ^=3 ft 
 
 as- 
 
 s ^ (d 
 
 ■g§§ 
 
 aw •' 
 
 -. o V 
 
 5 = 3 
 ■S'%s 
 o gS 
 
 a; to I 
 ill 
 
 6 •* 
 
 I "I' 
 
 <o 
 O 
 
206 
 
 THE ICE AGE IN NORTH AMERICA. 
 
 many as eight of those examined by Professor Koons were 
 upward of eight hundred feet long and about half as wide; 
 the rims from seventy-five to a hundred feet high. 
 
 Fia. 65— Map of western New York, showing distribution of moralnal deposits. (From 
 U. S. Geological Survey.) 
 
 West of the Hudson Valley, as we have already seen, it 
 is difficult to trace a well-defined and continuous moraine 
 along the extreme glacial boundary. Such a moraine is 
 pretty well made out across New Jersey and a portion of the 
 distance between the Delaware and Susquebanna Rivers in 
 Pennsylvania ; but, beyond, the country is mountainous, and 
 through a considerable portion of the way difficalt of ex- 
 ploration. Through central New York, however, there are 
 specially marked accumulations of glacial debris near the 
 water-partings between the St. Lawrence and Mohawk Val- 
 leys aiid that of the Susquehanna. President Chamberlin is 
 inclined to correlate the accumulations just south of the 
 " Finger Lakes " of that region f with the interior moraine 
 
 t "Preliminary Paper on the Terminal Moraine of the Second 
 Glacial Epoch," p. 353. 
 
TERMINAL M0BAINE8. 207 
 
 which we have described as running through Cape Cod, 
 EHzabeth Islands, the southern portion of Rhode Island, and 
 the northern part of Long Island, and also with those to he 
 described more particularly hereafter as the Kettle Range, 
 in Wisconsin. This interior line he would designate " the ter- 
 minal moraine of the second Glacial epoch." But, in order to 
 avoid the assumption of a distinct second Glacial epoch before 
 conclusive proof is presented, the happy phrase of Professor 
 Cook, of New Jersey, seems preferable, who would call the 
 marked accumulations in the region to the north of the gla- 
 cial limit " moraines of retrocession." Still, there is no great 
 impropriety in calling them simply terminal moraines, since, 
 wherever the ice-front paused for any length of time, a spe- 
 cial accumulation of debris would take place, and would be 
 terminal to the ice at that point. 
 
 West of the AUeghanies, President Chamberlin deline- 
 ates this moraine as extending in a series of lobes pointing to 
 the south across the States of Ohio and Indiana, making one 
 grand loop whose axis is nearly parallel with that of Lake 
 Erie, returning with its western arm into eastern Michigan, 
 between Saginaw Bay and the southern end of Lake Huron. 
 He discovers five minor loops in this moraine in the axes of 
 the following river valleys: (1) the Grand and Mahoning; 
 (2) the Sandusky and Scioto ; (-3) the Great Miami — all in 
 Ohio; (4) the White, in Indiana; and (5) the Maumee and 
 Wabash. But the accumulations called terminal in this re- 
 gion are by no means comparable in extent with those south 
 of New England or west of Lake Michigan, and the system 
 is made out with some difficulty. 
 
 In this portion of the territory there is another interior 
 morainic belt of such interest that we pause to describe it 
 more particularly. We refer to that of the Maumee Val- 
 ley in Ohio, and can best describe it in the words of Mr. 
 G. K. Gilbert, its original discoverer : 
 
 The Maumee River occupies the axis of the broad, shallow 
 valley which it helps to drain. This valley has no strongly 
 
208 THE ICE AGE IN NORTH AMERICA. 
 
 marked limits. Eastward it is continuous with the trough of 
 Lake Erie, and westward with the valley of the Wabash Kiver. 
 At the north, or more properly the northwest, its slopes merge, 
 at a height of five hundred to six hundred feet (above Lake Erie), 
 with those of the valley of Lake Michigan ; and its southern 
 slopes, reaching a height of four hundred to five hundred feet, 
 pass into those of the Ohio valley. With these low sides and a 
 width of 125 miles, all its inclinations are exceedingly gentle, 
 a.nd the title of plain can be applied to it with no less propri- 
 ety than that of valley. North of the Maumee the general de- 
 scent is to the southeast, and south of that river to the north- 
 east. With slight exceptions, the smaller streams follow and 
 indicate these slopes, but all the larger tributaries of the Mau- 
 mee, including the St. Joseph, St. Mary's, and Auglaize Elvers, 
 and Bean or Tiffin Creek, appear to be independent of them. 
 The St. Joseph, for example, flows to the southwest through a 
 country where eveiy rivulet runs to the southeast. The entire 
 region drained by it lies on its right bank, while from its left 
 the drainage is toward Bean Creek, the divide between the two 
 streams being everywhere within three or four miles of the St. 
 Joseph. In like manner, the course of the St. Mary's is west 
 and north, and, while from its left bank the streamlets flow 
 northeast into it, from its right they flow northeast into the 
 Auglaize. These hydrographical peculiarities are so singular 
 and striking as to have excited some attention and curiosity 
 before the region was visited. Upon examination, there was 
 found a continuous ridge, following the eastern banks of these 
 rivers, and evidently determining their courses. Running 
 somewhat obliquely across the slopes of the country, it turned 
 aside all the small streams, and united them to form the St. 
 Joseph and St. Mary's. The height of this ridge is ordinarily 
 from twenty-five to fifty feet, and its width at base from four 
 to eight miles. Along the St. Joseph it is not distinguished 
 from the adjacent country by its superficial characters. In 
 common with that, it has a gently rolling surface, with a grav- 
 elly clay soil, supporting a heavy growth of varied timber. 
 Farther south, where it forms the north bank of the St. Mary's 
 River in Van Wert and Mercer counties, it is marked by such 
 peculiarities as to divide it very sharply from the adjoining 
 
TERMINAL MORAINES. 209 
 
 plains, which are nearly level, with a soil of fine clay, and cov- 
 ej-ed by a heavy growth of elm, beech, ash, maple, etc. The 
 ridge, on the contrary, presents a confused series of conical 
 hills, chiefly of clay, but showing some pebbles and small 
 bowlders, and clothed by a forest-growth almost exclusively of 
 oak. Probably the only essentia! point in this contrast is that 
 of hill and plain, and out of this the others have grown. 
 There is good reason to believe that the clay deposit (Erie clay) 
 of the plain is continuous with that on the hills. Where its 
 surface is level, it has retained its soluble salts and accumu- 
 lated vegetable mold, so as to form a rich soil favorable to a 
 varied vegetation ; while from the steep hill-sides a great 
 amount of soluble and fine material has been washed, so as to 
 bring to the surface some of the pebbles everywhere imbedded 
 in greater or less abundance, and the character of the vegeta- 
 tion has been determined by that of the soil. 
 
 I conceive that this ridge is the superficial representation 
 of a terminal glacial moraine, that rests directly on the rock- 
 bed, and is covered by a heavy sheet of Erie cl"y, a subsequent 
 aqueous and iceberg deposit. Though this formation has an 
 average depth along the upper St. Joseph of over one hundred 
 feet, and on the upper St. Mary'c of fifty feet, it has not suf- 
 ficed to conceal a moraine of such magnitude, but has so far 
 conformed to its contour as to leave it still visible on the face 
 of the country — doubtless in comparatively faint relief, but 
 still so bold as to exert a marked influence on the hydrography 
 of the valley.* 
 
 "When, a little later, we come to speak of glacial erosion, 
 something more will be said confirmatory of this hypotheti- 
 cal moraine of Mr. Gilbert, and of the varying movements of 
 ice in the Lake Erie Valley at different stages of the Glacial 
 epoch. We shall then see abundant reason for supposing 
 that there was, for a considerable length of time about the 
 close of the period, an independent movement of ice in the 
 direction of the longer axis of the lake, and that this 
 
 * " On the Surface Geology of the Mauraee Valley," in the " Geological Sur- 
 vey of Ohio," vol. i, pp. 540-542. 
 
TERMINAL MORAINES. 211 
 
 movement was directly toward the head of the Maumee 
 Kiver. 
 
 The general system of interior moraines upon which we 
 were remarking is pretty well exhibited about the eastern 
 shore of Lake Michigan, forming a grand loop around that 
 lake, and connecting with two subordinate loops around the 
 head of Grand Traverse Bay and Saginaw Bay. But it is not 
 until reaching the country west of Lake Michigan, in "Wis- 
 consin, that these glacial accumulations become again a very 
 prominent feature of the landscape. Here they constitute 
 the so-called Kettle Kange, which forms a loop pointing to 
 the southwest in the line of the longer axis of Green Bay. 
 President Chamberlin has shown * that the ice-movement to 
 the southward through Green Bay was in a measure inde- 
 pendent of that through Lake Michigan ; so that the eastern 
 arm of the Kettle Bange might more properly be called a 
 medial moraine, to which the Lake Michigan Glacier and the 
 Green Bay Glacier both contributed their deposits. This 
 eastern arm runs about half-way between Fond du Lac and 
 Sheboygan, and thence a little west of south, through "Wash- 
 ington and "Waukesha counties, between Oconomowoc and 
 Pewaukee, and through Eagle to Milton, between Janesville 
 and Whitewater. Thence it swings northward, passing a few 
 miles west of Madison, and, crossing an elbow of the "Wiscon- 
 sin Eiver, incloses in its folds Devil's Lake, near Baraboo, 
 and thence on northward into the wilderness of northern 
 "Wisconsin, a little beyond the latitude of St. Paul, where it 
 turns westward and with some deflection reaches the St. Croix 
 River at Hudson, a few miles above its junction with the 
 Mississippi. From this point it trends southward past Min- 
 neapolis through southeastern- Minnesota, inclosing in its 
 folds Minnetonka and many other beautiful lakes in that 
 portion of the State. From this point on, Mr. ITpham has 
 traced the moraine in an ox-bow-shaped extension, whose 
 
 * " Preliminary Paper on the Terminal Moraine of the Second Glacial 
 Epoch,'' p. 315, et aeq. 
 
212 THE IGE AQE IN NORTH AMERICA. 
 
 southern extremity is near Des Moines, Iowa, and whose 
 western limb is the Coteau des Prairies of eastern Dakota. 
 
 The conclusions of Mr. Upham and President Chamber- 
 lin, concerning the movements of the ice over the region 
 west of the laies, are intensely interesting and seem amply 
 warranted by the facts. It appears that in the northwest the 
 ice advanced in four lines of motion pointing to a center a 
 little below Dubuque, Iowa, though the columns did not all 
 reach the point of their apparent destination : 1. One line 
 of advance was down the depression of Green Bay, in Wis- 
 consin. The moraine of this lobe constitutes what is called 
 the Kettle Range of that State, and terminates a little west of 
 Madison, on the eastern edge of the driftless region. 2. A 
 second line of movement was down the valley of Kewanee 
 Bay. This movement spent its force in northern Wisconsin, 
 reaching the vicinity of Eau Claire. 3. The third move- 
 ment was along the line of the main axis of the western end 
 of Lake Superior, and extended across the Mississippi past 
 Minneapolis, as far as Lake Minnetonka, and to a line run- 
 ning northwest from this point for a hundred miles or more. 
 4. The fourth movement was from the region of Lake Win- 
 nipeg in the Tied River Valley toward the south and south- 
 east, meeting and opposing the ice-current from Lake Supe- 
 rior, along a line from Steams county, Minn., southeast by 
 Lake Minnetonka to Crystal Lake in Dakota county. This 
 is the movement which extended southward to the vicinity 
 of Des Moines. Iowa, and whose western flank is the Coteau 
 des Prairies. 
 
 The line northwestward from Minneapolis, where these 
 last two movements met, was an interesting battle-ground of 
 the glacial forces. First, the Lake Superior Glacier pre- 
 vailed, and pushed over the ground to its extreme limit, 
 even beyond the Mississippi. This boundary-line runs from 
 Crystal Lake through Minnetonka, Wright, and Stearns 
 counties, Minn. A little later, the Red River Glacier 
 gained the ascendency, pushing the front of the Lake Supe- 
 rior Glacier back into Wisconsin, east of the Mississippi. 
 
TERMINAL MORAINES. 213 
 
 The reality of this battle of the glaciers, and of this alter- 
 nate advance and retreat of the opposing forces, is shown by 
 the succession of deposits. The lower part of the ground 
 moraine is characterized by a reddish color, and by rock- 
 fragments from the region of Lake Superior; while the 
 upper portion, now upon the surface, is of a bluish color, 
 containing bowlders and pebbles of limestone and of creta- 
 ceous shale, and other material brought from the northwest, 
 showing that victory was first to the Lake Superior Glacier, 
 but finally to that of the Eed River. 
 
 The evidence of the junction of these two great ice- 
 streams appears clearly enough upon the surface when sec- 
 tions of country a little distance apart are considered. This, 
 Dr. G. M. Dawson had observed as early as 1875, when he 
 wrote about it thus : 
 
 A line drawn northeast and southwest, nearly parallel with 
 the northwestern shore of Lake Superior, but lying a short dis- 
 tance back from it, and cutting the Northern Pacific Eailway 
 some miles west of Thomson, in this part of Minnesota, sepa- 
 rates superficial deposits of different aspects. Northwest of 
 this line the prevailing tint of the drift material is pale yellow- 
 ish-gray, or drab ; southeast of it, reddish tints are almost 
 universal, and become specially prominent on the northern 
 part of the line of the Lake Sujierior and Mississippi Eailway, 
 and continue to St. Paul. The junction of these two varieties 
 of drift can not, of course, be exactly defined, but is interest- 
 ing as an indication of the direction of transport of material 
 in this region ; the reddish matter being derived from the red 
 rocks of the lake-shore.* 
 
 Some other interesting things concerning the deposits of 
 this region can better be said when we come to treat of gla- 
 cial dams and lakes, and of the cause of the Glacial period. 
 
 The surprising thing to a glacialist, upon a first visit to 
 
 * " Report on the Forty-ninth Parallel," p. 213. See also " The Fresh- Water 
 Grlacial Drift of the Northwestern States," p. 9, by Colonel Charles Whittlesey,. 
 who, it would seem, had noted the distinction as early as 1866. 
 
214 THE ICE AGE IN NORTH AMERICA. 
 
 soutteastern Dakota, is the ertensiveness of tlie apparently 
 level areas where the till comes to the surface. This impres- 
 sion is heightened, probably, by the absence of forests, and 
 would yery likely be the same in portions of Ohio and 
 Indiana were it not for the timber. James Kiver Valley, in 
 Dakota, is depressed in the center about five hundred feet 
 below the edges, but it is, roughly speaking, seventy miles 
 across, and therefore the slope does not strike the eye. So 
 level is the country, that every special line of glacial accu- 
 mulation is a prominent feature in the landscape, and the 
 various halting-places of the ice in its retreat are readily dis- 
 cerned. Evidently, a lobe of ice for a long time filled the 
 James River VaUey, running parallel with that which occu- 
 pies the upper Minnesota Valley, and extended southward 
 into Iowa. The edges of these lobes thinned out along the 
 north-and-south line which runs near the east margin of 
 southern Dakota, and favored the accumulation of the mo- 
 raihic hills, to which we have already referred as the Coteau 
 des Prairies. Professor Todd and others speak of this as a 
 series of terminal moraines formed along the sides of the re- 
 entrant angle, between the two lobes, whose apex penetrated 
 to the vicinity of the Sisseton Agency. Perhaps, however, 
 it would facilitate a proper understanding of the subject to 
 speak of the Coteau des Prairies as a medial moraine, like 
 that east of Green Bay, toward which the glacial debi'is, 
 carried on the deeper portions of the ice of both the Minne- 
 sota Piver and James River lobes, gravitated in contrary 
 directions. But, whatever the name, certain it is that, start- 
 ing from the Sisseton Agency, different lines of glacial accu- 
 mulations stretch southward at varying angles, the later 
 accumulations forming the more obtuse angle. Coming up 
 the valley of the James from Yankton, one crosses the old- 
 est of these accumulations (the Altamont Moraine) in the 
 neighborhood of the city itself, and the second (or Gary 
 Moraine) in the neighborhood of Mitchell, sixty miles to the 
 north, having run parallel with it, however, for about thirty 
 miles. The third (or Antelope Moraine) is encountered near 
 
TERMINAL MORAINES. 215 
 
 Huron, about sixty miles north of Mitchell, and continues 
 visible upon either side of the river about twenty miles dis- 
 tant, as far up as Aberdeen. 
 
 The western side of this lobe is characterized by corre- 
 sponding lines of receding moraines, the outer of which is in 
 the vicinity of the Missouri Eiver and on its eastern side. 
 Together, these form the Missouri coteau. Everywhere, in 
 coming up from the river on the west to the plateau, which 
 is in most places from four hundred to five hundred feet 
 above the river, one encounters two or three bowlder-cov- 
 ered terraces, the highest of which are at an elevation of 
 from three hundred to four hundred feet. The moraines 
 rise to a considerable height above the general level, and, as 
 upon the eastern side, are everywhere marked features of the 
 landscape. The streams entering the Missouri from the east 
 are all of them short, none being more than forty miles in 
 length. These streams are in all cases bordered by broad 
 and elevated local terraces, the edges of which, where they 
 overlook the immediate trough of the stream, are crowded 
 with granitic bowlders. In some cases, as Professor Todd 
 has shown, these valleys terminate abruptly in the water- 
 parting, as if being the continuation of glacial streams from 
 the east, which had originated upon the ice-lobe while it 
 filled the James Valley. 
 
 Professor Todd, to whom the exploration of this region 
 was assigned, thus describes the Missouri coteau : 
 
 This moraine consists of loops, convex usually toward the 
 west and south, but in rare cases toward the northwest, as will 
 be seen. These loops connect at re-entrant angles pointing 
 toward the northeast and east, which are usually sharp, and 
 sometimes are extended into elongated ridges. The moraine 
 varies in elevation with the region on which it rests. Its rela- 
 tive height is usually great at the head of bhe re-entrant 
 angles or interlobular moraines. These frequently stand out 
 like great promontories, rising from one hundred and fifty to 
 four hundred feet above the plain around them. At the bot- 
 tom of a loop the moraine is apt to be slight or wanting, if on 
 
WjCMjSSS 
 
 cr.AMm} ^ 
 
 iChaifiEerlaSE' \ , .. 
 
 SKETCH MAP) 
 
 OFTIIE 
 
 
 MISSOURI COTEAU ^^^ 
 
 AND ITS 
 
 MORAINES. 
 
 By J. E. TODD, 
 
 Asat. Oeologiat U. S. O. S>- 
 
 v^'/i-AisiJji: Moraines 1,2, S d: a. 
 
 Contours 
 
 Railroads 
 
 ,^^-.x^~ Limit of Drift 
 
 •',•> Shore of Lake Dakota 
 
 
 
 
 ^%5s 
 
 Fio 67. 
 
TERMINAL MORAINES. 217 
 
 lower land ; the flow of water from the ice probably having 
 carried away the debris as rapidly as it was pushed forward by 
 the ice. On the other hand, in case the loop was pushed up 
 an inclined plane, and the water did not find free escape, it 
 (the loop) is well developed all around. The outer moraine in 
 some places is very rough and stony ; at other points it is a 
 smooth, broad ridge, with few knobs, and covered with a deep, 
 fertile soil.* 
 
 Dr. G. M. Dawson early discovered the significance of 
 this great Missouri coteau in its extension north of the 
 United States boundary-line, and thus describes it : 
 
 On approaching its base, which is always well defined at a 
 distance, a gradual ascent is made, amounting, in a distance of 
 twenty-five miles, to over 150 feet. The surface at the same 
 time becomes more markedly undulating, as, on nearing Turtle 
 Mountain from the east, till almost before one is aware of the 
 change, the trail is winding among a confusion of abruptly 
 rounded and tumultuous hills. They consist entirely of drift 
 material ; and many of them seem to be formed ialmost alto- 
 gether of bowlders and gravel, the finer matter having been to 
 a great extent washed down into the hollows and basin-like 
 valleys without outlets with which this district abounds. The 
 ridges and valleys have in general no very determined direc- 
 tion, but a slight tendency to arrangement in north-and-south 
 lines was observable in some places. 
 
 The bowlders and gravel of the coteau are chiefly of Lau- 
 rentian origin, with, however, a good deal of the usual white 
 limestone and a slight admixture of the quartzite drift. The 
 whole of the coteau belt is characterized by the absence of 
 drainage valleys ; and, in consequence, its pools and lakes are 
 often charged with salts, of which sulphates of soda and mag- 
 nesia are the most abundant. The saline lakes frequently dry 
 up completely toward the end of the summer, and present 
 wide expanses of white efflorescent crystals, which contrast in 
 
 * " Proceedings of the American Association for the Advancement of Sci- 
 ence," vol. xxxiii, 1884, p. 383. 
 
TERMINAL MORAINES. 
 
 219 
 
 color with the crimson Salicornia with 
 which they are often fringed. 
 
 Taking the difference of level hetween 
 the last Tertiary rocks seen near the east- 
 ern hase of the coteau and those first found 
 on its western side, a distance of about sev- 
 enty miles, we find a rise of six hundred 
 feet. The slope of the surface of the under- 
 lying rock is, therefore, assuming it to be 
 uniform, but little more than four feet 
 per mile. On and against this gently in- 
 clined plane the immense drift deposits of 
 the coteau hills are piled. 
 
 The average elevation of the coteau above 
 the sea, near the forty-ninth parallel, is 
 about 2,000 feet ; and few of the hills rise 
 more than one hundred feet above the gen- 
 eral level. 
 
 Between the southwestern side of the 
 coteau belt and the Tertiary plateau is a 
 very interesting region with characters of 
 its own. Wide and deep valleys with sys- 
 tems of tributary coulees have been cut in 
 the soft rocks of the northern foot of the 
 plateau, some of which have small streams 
 still flowing in them fed by its drainage ; 
 but for the most part they are dry, or oc- 
 cupied by chains of small saline lakes which 
 dry up early in the summer. Some large 
 and deep saline lakes also exist which do 
 not disappear even late in the autumn. 
 They have a winding, river-like form, and 
 fill steep-sided valleys. These great old 
 valleys have now no outlet ; they are evi- 
 dently of preglacial age, and have formed 
 a part of the former sculpture of the coun- 
 try. The heaping of the great mass of 
 debris of the coteau against the foot of the 
 Tertiary plateau has blocked them up and 
 
 I 
 
 I 
 
 s ■ 
 £^ 
 
 ■SeS 
 
 a 
 
 .a 
 
 I 
 
 m 
 
220 THE ICE AGE IN NORTH AMERICA. 
 
 prevented the waters finding their way northward as before ; 
 and, since glacial times, the rainfall of the district has never 
 been sufficiently great, in proportion to the evaporation, to 
 enable the streams to cut through the barrier thus formed. 
 The existence of these old valleys, and the arrangement of the 
 drift deposits with regard to them, throw important light on 
 the former history of the plains. 
 
 Northward, the coteau ceases to be identified with the Ter- 
 tiary plateau, and rests on a slope of cretaceous rocks. It can 
 be followed by Palliser's and Hector's descriptions of the coun- 
 try to the elbow of the South Saskatchewan, and thence in a 
 line nearly due north through the Eagle and Thickwood Hills ; 
 beyond the North Saskatchewan, however, it appears to be- 
 come more broken and less definite. In Dr. Hector's descrip- 
 tion of certain great valleys without outlet in this northern 
 region, I believe I can recognize there, too, the existence of 
 old blonked-up river-courses similar to those just described. 
 
 South of the forty-ninth parallel the continuation of the 
 belt of drift material can also be traced. It runs southeast- 
 ward, characterizing the high ground between the tributaries 
 of tlie Missouri and the Eed Eiver, which has already been 
 noticed in connection with the water-shed of the continent ; 
 but, wanting the backing of the lignite Tertiary plateau, it 
 appears to become more diffuse, and spread more widely over 
 the country. That the drift deposits do not form the high 
 ground of the water-shed, but are merely piled upon it, is evi- 
 dent, as cretaceous rocks are frequently seen in its neighbor- 
 hood at no great depth. . . . 
 
 In the coteau, then, we have a natural feature of the first 
 magnitude— a mass of glacial debris and traveled blocks with 
 an average breadth of perhaps thirty to forty miles, and ex- 
 tending diagonally across the central region of the continent 
 for a distance of about eight hundred miles.* 
 
 To one familiar with the literature of the subject, it 
 would seem that Dr. Dawson's sagacity in thus early dis- 
 
 * "Quarterly Journal of the Geological Society," vol. xxxi (November, 
 1875), pp. 614-616. The facts are more fully stated in his governmental " Re- 
 port on the Forty-ninth Parallel." 
 
TERMINAL MORAINES. 221 
 
 ceming the great significance of tlie Missouri coteau has not 
 received from glacial writers all the recognition it fairly 
 deserves. But here we have, as in so many other instances, 
 fresh illustration of the fact that the minds of sagacious 
 investigators run in the same channel. Noteworthy in- 
 ventions and discoveries are not often due to the work of 
 single individuals. From the references already given, it 
 would appear that Dr. Dawson's surmise as to the signifi- 
 cance of the Missouri coteau. President Chamberlin's theory 
 as to the meaning of the Kettle Range, Professor Cook's 
 delineation of the moraine across New Jersey, and Clar- 
 ence King's interpretation of the glacial accumulations on 
 the south shore of Massachusetts were, in the minds of 
 the authors, nearly contemporaneous and of independent 
 origin. 
 
 The subject of this chapter will not be complete without 
 speaking of those later and more local moraines which were 
 formed when the ice had withdrawn itself from the country 
 in general, but still lingered everywhere in the mountains. 
 Such moraines are numerous in all the valleys of the White 
 Mountains. Professor Agassiz * describes no less than fifteen 
 terminal moraines of small size crossing the valley of the 
 Ammonoosuc, a short distance below Bethlehem. Similar 
 moraines exist in the valley leading down the Saco near 
 Bartlett, and in the White Mountain branches of the Andros- 
 coggin, as well as in the valleys leading to the vicinity of 
 Center Harbor, on Lake Winnepesaukee. The principal local 
 moraine of the Androscoggin is near the State line between 
 Shelbume, N. H., and Gilead, Me. This has been described 
 by Professor Stone and others.f Other interesting moraines 
 described by Professor Stone in Maine are located at Read- 
 field Village, and at Swan Island in the Kennebec Valley, 
 and at Sabbattusville, Machias, and Waldoboro. 
 
 Among the innumerable instances of local moraines on 
 
 * " Geology of New Hampshire," vol. iii, pp. 236-238. 
 
 f "American Journal of Science," vol. cxxxiii, 1887, p. 379. 
 
222 THE ICE AGE IX XOHTS AilEEIGA. 
 
 the Pacific slope, the following, described by Mr. I. C. Rti&- 
 sell, may serve as specimens : 
 
 If one proceeds up the cation [of Leevining Elver, Mono 
 county, California], he will cross five or six small terminal mo- 
 raines which traverse from side to side the broad trench left 
 by the ancient glacier. These are seldom more than fifteen or 
 twenty feet high, and are separated by grassy meadows. The 
 creek was formerly dammed by these moraines and forced to 
 expand so as to form small lakes ; but these have long since 
 been drained by the cutting of channels through the obstruc- 
 tions.* 
 
 Other instances have been already mentioned in describ- 
 ing the glaciated boundary in Colorado, southern Califorma, 
 Oregon, and the State of Washington. Moraines of retroces- 
 sion characterize almost every mountain valley which was 
 occupied by ice during the Glacial period. 
 
 The distribution of till in North America has been the 
 subject of an immense amount of investigation during the 
 past few years, accounts of which will be found in the vari- 
 ous scientific journals and State reports. Most prominent of 
 all are those carried on by Mr. Frank Leverett, Professor 
 Geo. H. Stone, and Dr. Warren Upham of the United States 
 Geological Survey, and embodied in the monographs on the 
 "Glacial Formations and Drainage Features of the Erie and 
 Ohio Basins," "The Illinois Lobe," "The Michigan Glacial 
 Deposits" (by Leverett); "The History of Glacial Lake 
 Agassiz" (by Upham); and the "Glacial Deposits of Maine" 
 (by Stone). 
 
 From these it appears that there are no less than twelve 
 moraines traceable across Ohio between Cincinnati and Lake 
 Erie, all belonging to the last, or so-called Wisconsin Episode; 
 these follow very irregular lines, and are not always easy of 
 recognition. Evidently they are moraines of recession, indi- 
 
 *"Quaternary History of Mono Valley, California," p. 334. 
 
TERMINAL MORAINES. 223 
 
 eating points where there was a marked pause in the retreat 
 of the front, affording time for a considerable accumulation 
 of material, and perhaps sometimes of a short advance. 
 These well defined morainic deposits mark a movement from 
 Labrador as a center, and over a considerable area overrode 
 earlier deposits which had been laid down by the movement 
 from the Keewatin center west of Hudson's Bay. The Wis- 
 consin moraines are well developed across New Jersey and 
 Pennsylvania down to the line surveyed by Professor Cook 
 and by Lewis and Wright as marked on our map. West of this 
 the glaciated area in Ohio and Indiana was covered with Wis- 
 consin drift down close to the southern border; while in Illi- 
 nois it reached well down towards the center of the state, and 
 in Iowa projected in a well defined loop as far as Des Moines, 
 and in the Dakotas extended to the Missouri River. 
 
 An earlier movement from the same center is denominated 
 the lUinoisan. This projected beyond the Wisconsin deposits 
 over nearly all the western portion of Illinois, and crossed the 
 Mississippi River for a short distance in the neighborhood of 
 Burlington, compelling the river to flow for a short period in 
 a new channel that can be traced from Clinton to Lee County, 
 Iowa. Jaspar conglomerate bowlders from north of Lake 
 Huron are found, with more or less frequency, over the whole 
 region covered by the Wisconsin and lUinoisan deposits 
 lying west of Pennsylvania and southeast of a line connecting 
 Des Moines, Iowa and Green Bay, Wisconsin. 
 
 Outside of the lUinoisan area there is in Iowa a still earlier 
 pretty well defined series of deposits called the lowan. Mr. 
 Leverett, however, does not now feel like recognizing these 
 as distinct from the other deposits. But there is a very well 
 defined line some distance outside the Wisconsin deposits, 
 running across the state from east to west and nearly through 
 the middle, separating an area which is covered by loess and 
 one which is bare of loess, the loess evidently having been 
 derived from the ice of the northern portion as it was swept 
 
224 THE ICE AGE IN NORTH AMERICA. 
 
 off by the melting waters. But of this we will speak more 
 particularly when treating of the loess. 
 
 Still outside of the lowan and the Illinoisan deposits there 
 is a vast area in Southern Iowa, Northern Missouri, and 
 Eastern Nebraska and Kansas, which is covered with a still 
 older till, denominated Kansan. This till is much more 
 thoroughly oxidized than the other, and is spread more evenly 
 over the surface with an entire absence of moraines. Still 
 farther east (in Illinois, Indiana, Ohio, Pennsylvania, and New 
 Jersey) there is also frequently found an attenuated border 
 of glacial material which is correlated with the Kansan, from 
 its having many of the same characteristics. It is more 
 completely oxidized, more evenly spread over the area, and 
 is devoid of moraines. It nov^' seems clear that this Kansan 
 till is the result of a movement of ice which preceded those 
 which deposited the other sheets of till and, moving east- 
 ward covered a large part of the field which is now enveloped 
 with lowan, Illinoisan and Wisconsin deposits. The extent 
 of this eastward movement is not generally appreciated. But 
 Professor E. H. Williams found Lake Superior copperfirmly 
 imbedded in "Kansan till," forty feet below the surface, 
 at East Warren, Pennsylvania, several hundred miles east of 
 the source of supply. 
 
 A still earlier glacial deposit has been recognized by the 
 geologists of Iowa at Afton near the southern line of the 
 State, and hence called the Aftonian Episode. This is recog- 
 nized both by its position underneath the Kansan till and 
 by its excessive oxidization. But, owing to its position it 
 does not offer itself to inspection in many places, and even 
 where it is visible its true age is a matter of speculation. 
 
 The earliest of all drift sheets is thought to have been 
 recognized by Dr. George M. Dawson in the Province of 
 Alberta, east of the Rocky Mountains, in Southern Canada, 
 while Professor Calvin has discovered what he thinks is a 
 Sub-Aftonian till in Iowa, which may correspond to that 
 described by Dr. Dawson. 
 
TERMINAL MORAINES. 225 
 
 The main evidence of the age of these deposits •will come 
 up for discussion when we consider the date of the glacial 
 period in general and of its various episodes. (See chapter XX, 
 pp. 580-592). 
 
 But it will be in place to give expression at this point to 
 some cautions against premature judgments respecting the 
 evidence. It is important to keep in mind (1) the fact that 
 there is no valid objection to the supposition that geological 
 changes proceed much more rapidly at some periods than at 
 others. Indeed it is a fundamental doctrine of evolution 
 that cumulative strains in the earth's crust may go on un- 
 noticed for an indefinite period until the limit of resistance 
 is reached, when there will be a rapid readjustment which 
 may well deserve the name of catastrophe. Preglacial 
 elevation proceeded all through the latter portion of the 
 Tertiary Period until the snows of the Glacial Period pro- 
 duced the ice age, when the very weight of the ice facilitated 
 the subsequent depression and the rapid return to the ocean 
 of the water that had been locked up in the continental 
 glaciers. In this accumulation of ice over the northern 
 hemisphere and its subsequent return to the ocean there is 
 brought to light a force of such incalculable power affecting 
 the elevation and depression of the land that the effects are 
 entirely abnormal to our present experience. We cannot 
 reason back from the rate of present changes to that of 
 the Glacial Period. 
 
 (2) Again, we are never at liberty to lose sight of the fact 
 that a long period of disintegration of the rocks over the gla- 
 ciated region preceeded the ice age. The rocks over that 
 region were then rotted to a great depth as they are now in 
 the region south of the ice limit. This furnished an immense 
 amount of oxidized material for the first grist of the glacial 
 mill, and that was spread widely over the southern margin 
 of the glaciated area. 
 
CHAPTER X. 
 
 GLACIAL EROSION ANII TRANSPORTATION. 
 
 The extent of glacial erosion is a hotly contested questioB. 
 One class of wiiters has gone to the extreme of attributing 
 almost all the erosion of the higher latitudes to glacial action, 
 
 I' iG. iO.— Canon of the tolorudo. Stieaiii-yiobion in a drj cliniatf. (Neubcn\.> 
 
 while another class has scarcely allowed any eroding power 
 to glacial ice, in com])arison with that of running water. 
 In considering the relative importance of these agencies. 
 
OLAVIAL EROSION AND TRANSI'OUTATIOX. 227 
 
 two elements enter into the pi'oblem : (1) the relati\'e rate of 
 action of the two forces, and (2) the relati\'e length of time 
 during wliicii they have been in operation. 
 
 As to time, it is evident that those have a great advantage 
 in the argument who exalt the eroding power of ruiming 
 water. However slowly the drops may wear away the stone, 
 ample amends are made in the length of the periods thi'ough 
 which the action has continued. From the earliest ages of 
 geological history running water has been at work counter- 
 acting the effect of the forces which have elevated the con- 
 tinents. River - channels are, in fact, more constant than 
 mountain-chains. Everywhere and at all times the aecumu- 
 
 F[(. 71.— Enilinssed floor of an ancient irlacier in the valley of the npi>er Arkansas River. 
 
 (Hayden.) 
 
 latino- waters on a continental area seek and find the lowest 
 paths to the sea. The sand and gravel which these running 
 streams push along over their beds act as the teeth of a saw 
 upon the rising mountain-summits, so that everywhere in 
 mountain-regions of great age we find deep, transverse ^al- 
 
228 THE ICE AGE IN NORTH AMERICA. 
 
 leys of erosion. Among the best-known examples in the 
 country are those of the Mohawk and Hudson in New York ; 
 of the Delaware and Susquehanna in Pennsylvania; the 
 Ohio and its tributaries on the western flanks of the AUe- 
 ghanies ; the Mississippi and all its western branches, together 
 with the Colorado upon the eastern flanks of the Rocky 
 Mountains ; and the Columbia, the Eraser, and the Stickeen 
 Elvers, which penetrate in chasms of great depth the rock- 
 bound shore of the Pacific. 
 
 At the Delaware Water-Gap the river has sawu a vertical 
 chasm more than a thousand feet deep directly across the 
 hard strata of the Kittatinny Mountain. For fifty miles 
 above Lock Haven, on the West Branch of the Susquehanna, 
 the river occupies a narrow valley of erosion more than a 
 thousand feet in depth. For nearly twelve hundred miles, 
 as the water runs, the Ohio Eiver, with its extension up the 
 Alleghany, occupies a narrow, crooked valley, one mile or 
 more in width and several hundred feet in depth, which it 
 has worn through nearly parallel strata of lime and sandstone 
 rock. The trough of the Mississippi from Cairo upward is 
 similar to that of the Ohio, except that it is two or three 
 times as broad. The canons of the Colorado, of the Yellow- 
 stone, and of the Columbia, are of world-wide renown. The 
 Colorado has worn a channel with nearly perpendicular sides 
 three hundred miles long and from three to six thousand 
 feet deep.* Such are some of the well-recognized results 
 produced by the long-contimied mechanical action of running 
 water. 
 
 But, aside from its mechanical action, water with the 
 acids it contains is a most eflicient chemical force, acting as a 
 solvent upon various rocks. Every salt-spring and every 
 spring of hard water in a limestone region is undermining 
 the country from which it issues, and is engaged in dissolving 
 the solid material and in transporting it in solution to lower 
 levels. It is only a question of time when the chalk cliffs of 
 
 * "Elements of Geology," by Joseph Le Conte, pp. 15-11. 
 
GLACIAL EROSIOK AND TRANSPORTATION: 229 
 
 England and the extensive lime formations of the Appala- 
 chian region in America shall all be dissolved and carried in 
 invisible solutions to the sea. The Mammoth Cave is but 
 the remnant of larger, longer, and more numerous caverns 
 which have honey-combed vast regions in Kentucky and in 
 Tennessee. Many of the extensive valleys of that region are 
 but the depressions formed by the falling in of the roofs of 
 innumerable caverns. 
 
 The rate of chemical erosion on limestone rocks is not 
 easy to estimate. The most elaborate attempt of which I am 
 aware is that of Professor A. L. Ewing in the Nittany Yal- 
 ley, of Huntingdon county. Pa.* 
 
 This valley, which is known by different names, extends 
 through a considerable portion of the Appalachian region. It 
 consists of the remains of a great anticlinal fold, which, had it 
 not been eroded away, would form an immense mountain-like 
 plateau over 20,000 feet above its present height. As it is, the 
 floor of the valley is composed of the upturned edges of the 
 lower Silurian limestone, eroded through a thickness of 6,000 
 feet. The valley is flanked on either side by the overlying 
 Medina sandstone, which forms monoclinical ridges from 600 
 to 1,000 feet above its floor. 
 
 From data carefully collected, Professor Ewing ascer- 
 tains that the amount of solid matter annually carried out of 
 the valley in chemical solution is equal to a layer of g^}, ^ of 
 a metre in thickness. Hence, to lower the surface to the ex- 
 tent of one metre by this process would require 29,173 
 years — that is, it would take about 9,000 years to remove one 
 foot from the surface. 
 
 It is safe to assume that had the rocks of this region been 
 similar to those of the bordering mountains in their nature and 
 power td resist dynamical agencies, we should have in place of 
 Nittany Valley a mild anticlinal plateau somewhat above the 
 
 * See " Proceedings of the American Association for the Advancement of 
 Science," vol. xxxiii, 1884, p. 404. The paper was published in the "Second 
 Geolo^cal Survey of Pennsylvania, T'," pp. 451-464. 
 
230 THE ICE AGE IN NORTE AMERICA. 
 
 mountains in elevation — say 1,000 feet above the present 
 height of the valley. 
 
 The erosion in the valley, then, in excess of that along the 
 mountains has been mainly chemical, and at least a thousand 
 feet of limestone have been thus removed. A simple further 
 deduction shows that, accordingly, Nittany Valley has been 
 one million years in process of formation. 
 
 The limestone erosion could not begin before the latter 
 stages of the Mesozoic era, possibly not before the Cenozoic 
 era, as suflBcient time must have elapsed subsequent to the Car- 
 boniferous age to erode all formations of the Palaeozoic era 
 above the Trenton limestone. One million years seems not in- 
 consistent with other estimates of geological time. 
 
 In view of such facts the advocate of glacial erosion can 
 not continue to maintain that ice is the chief agency in form- 
 ing the contour of continental areas ; but must grant that, 
 by reason of the great length of time during which water 
 has been about its work of corrosion and erosion, it is, with- 
 out doubt, the most important instrument in diversifying the 
 features of the earth's surface. Still, however short, by com- 
 parison, have been the periods of glacial action, no one can 
 study a glacier or a glaciated region without being deeply 
 impressed with the eroding and transporting power of mov- 
 ing ice. To get a full conception of its erosive power, one 
 must either get beneath it, or be able to calculate the force 
 of its movement from what he knows of the natm-e of ice. 
 ISTeither of these plans is altogether satisfactory, but each of 
 them is to some extent feasible. 
 
 From the nature of the elements at work it has qirS 
 generally been supposed that an advancing glacier would act 
 like a plow or scraper, greatly disturbing and modifying the 
 deposits over which it passed. But observation and a more 
 careful consideration of the qualities of ice have material^ 
 modified these early impressions. From the fact that a 
 stream of ice moves faster at the top than at the bottom, it 
 follows that its action on underlying deposits is more like 
 that of a drag than like that of a plow. The rockj' frag- 
 
OLAGIAL EROSION AND TBANSPOBTATION. 231 
 
 ments frozen into the bottom of the ice are not held there by 
 a perfectly firm and unyielding grasp. The same bowlder 
 which plows a furrow in the rock beneath it, plows a loager 
 furrow in the ice which is . moving over it. This is finely 
 illustrated by some observations of Professor Niles. 
 
 In a visit to the great Aletsch Grlacier, in the summer of 
 1878, Professor Niles had an excellent opportunity to exam- 
 ine the under side of the ice of this glacier near its front. 
 Here he observed numerous elongated ridges of rock over 
 which the ice was flowing lengthwise, adjusting itself to all 
 the corrugated surface. When the ice passed the lee end of 
 the ridge it carried with it " the mold of the profile so per- 
 fectly that for more than twenty feet the blue arch presented 
 a series of parallel furrows, like the flutings of a Doric 
 column." 
 
 There was there at that time another highly interesting and 
 instructive exhibition of glacial action. Within a few feet of 
 the down-stream end of one of these elongated roches mouton- 
 nees and upon its crest, there was a bowlder fully three feet in 
 diameter, which evidently had been slowly moving along this 
 ridge for some distance, probably from its upper end. There 
 were two sides of this block of stone which were not incased in 
 ice, viz., the lower one resting upon the rock, and the one 
 facing down the glacier. From the lower end of the ridge of 
 rock I looked at the bowlder through a tunnel of jiure, blue 
 ice, which was continued as a deep furrow in the under sur- 
 face of the glacier for fully thirty feet from its beginning. As 
 this was produced by the ice moving over and beyond the 
 bowlder, it was evident that the ice was moving more rapidly 
 than the stone. I a^ erward found other examples of the same 
 kind, but none so favorably situated for a striking exhibition of 
 this property of ice. It will be understood that these stones 
 were suflBciently below the upper surface of the glacier to be 
 removed from the effects of the ordinary changes of the tem- 
 perature of the atmosphere. Although stones which are ex- 
 posed to such changes may be frozen into the ice at the edges 
 of the glacier, yet I believe these were so situated as to cor- 
 
232 THE ICE AGE IN NORTH AMEBIGA. 
 
 rectly represent the conditions and movements of this at still 
 greater depths. If this is correct, and I believe it is, it follows 
 that such fragments of rock are not rigidly held in fixed posi- 
 tions in the under surfaces of glaciers and carried irresistibly 
 along at the same rate, but that the constantly melting ice 
 actually flows over them, and that their motion is one of ex- 
 treme slowness, even when compared with the motion of the 
 glacier itself.* 
 
 In a visit to the glaciers of Norway in 1886, Professor J. 
 W. Spencer found abundant confirmation of Professor Giles's 
 inferences concerning the low eroding power of glaciers in 
 certain conditions. He reports that the advancing Nor- 
 wegian glaciers '" do not conform to the surfaces over which 
 they pass, but are apt to arch over from rock to rock and 
 point to point, especially as they are descending the ice-falls." 
 
 Professor Spencer continues : 
 
 Beneath the glaciers of Fondal, Tunsbergdal, and Buardal, 
 in the northern, north-central, and south-central snow-fields 
 of Norway, as well as under other glaciers, I observed many 
 stones inclosed in ice resting upon the rocks, to whose surfaces 
 — sometimes flat, sometimes sloping steeply — ^they adhered by 
 friction and by the pressure of the superincumbent weight. 
 Although held in the ice on four sides with a force pushing 
 downward, the viscosity of the ice, or the resistance of its 
 molecules in disengaging themselves from each other in order 
 to flow, was less than that of the friction between the loose 
 stones and the rock ; consequently, the ice flowed around and 
 over the stones, leaving long grooves upon the under surfaces 
 of the glacier. 
 
 An example of the ability of the ice to flow like a plastic 
 body was shown in a cavern four hundred feet higher than the 
 end of the glacier, where the temperature was 4° C, while that 
 outside was 13° 0. Upon the debris of the floor rested a 
 rounded bowlder, whose longer diameter measured thirty inches. 
 A tongue of ice, in size more than a cubic yard, was hanging 
 
 * " American Journal of Science," vol. cxvi, 1878, p. 366 et seq. 
 
GLACIAL EROSION AND TRANSPORTATION. 233 
 
 from the roof and pressing against the stone. In place of push- 
 ing the stone along or flowing around it, the lower layer of ice 
 above the tongue had yielded, and was bent backward as easily 
 and gracefully as if it had been a thin sheet of lead, instead of 
 one of ice a foot thick. 
 
 The insufiSciency of glaciers to act as great erosive agents 
 is further shown at Fondalen, where a mass of ice thirty or 
 forty feet thick abuts against a somewhat steep ridge of a rock 
 ten feet or less in height. In place of a stone-shod glacier 
 sliding up and over the barrier, the lower part of the ice 
 appears stationary, or else is moving around the barrier, while 
 the upper strata bend and flow over the lower layers of ice.* 
 
 The whole body of facts concerning a ground moraine 
 speaks- in like manner of the limited amount of disturbance, 
 in certain conditions, which is produced by the ice as it 
 moves over loose material. There can be little doubt that, 
 for a breadth of a hundred miles or more on the border of 
 the glacial limit in North America, the ice advanced over 
 the loose material (which is variously called " bowlder-clay," 
 " till," and " ground moraine ") without greatly disturbing it 
 as a body. Indeed, this great mass of firmly compacted, 
 unassorted, and glaciated material would seem to have ac- 
 cumulated by degrees — the moving ice, dragging along under 
 it successive strata of the grist which it had ground from the 
 surface of the rocks far to the north, where its action had 
 been more vigorous and long continued. For another strik- 
 ing illustration of the power of ice thus to move for a limited 
 distance over loose material without disturbing it, one has 
 but to refer to the description already given of the buried 
 forest near the southwestern comer of the Muir Glacier, 
 Alaska.f Here large trees in great numbers, which have 
 been preserved for an indefinite period underneath the gla- 
 cier, are now being uncovered, and appear standing upright 
 
 * Sue " Glacial Erosion in Norway and in High Latitudes," reprinted from 
 "Proceedings of the Koyal Society of Canada," IBS'?; extracted from "Ameri- 
 can Naturalist," vol. xxii, 1888, pp. 218, 221, 223. 
 
 f See p. 65. 
 
234 THE ICE AGE IN NORTH AMERICA. 
 
 with their branches intact upon them, and their roots im- 
 bedded in the soil in which they grew. A stratum of this 
 soil even consists of moss and leaves and cones which origi- 
 nally formed a carpet over the forest floor. There can be no 
 doubt that, after the accumulation of sand burying the forest, 
 the glacier advanced for a great distance over it, attaining 
 a thickness at that point of two or three thousand feet. 
 
 ' A little reflection will show that the advance of a glacier- 
 upon a new field is analogous to that of the breakers in the 
 ocean over shallow bottoms, though the impressiveness of the 
 scene is disguised to the physical senses by the slowness of 
 the movement in the case of a glacier, and by the counteract- 
 ing effect of the heat which limits the advance of the ice-front. 
 Where the ice-movement is upon dry land, the front is ordi- 
 narily represented by a sloping field of ice covered with 
 debris deposited from the melting surface near its terminus. 
 For a long time investigators were puzzled by the fact that 
 many bowlders are found some miles south of the line mark- 
 ing the limit of glacial scratches upon the surfaces of the 
 rocks. But, in the light of the previous suggestions, it is 
 easy to see that for some distance back from the southern 
 margin there could have been no movement at all at the 
 bottom of the ice, so that bowlders upon the surf ace might 
 be transferred, as upon the summit of a breaker, from some 
 distance back of the front to some distance beyond the far- 
 thest limit attained by the lower strata of moving ice. This 
 narrow belt of glacial deposits bordering the limit indicated 
 by other glacial signs constitutes what Professor Lewis and 
 myself * agreed to call " the fringe " of the terminal moraine. 
 West of the Alleghanies this fringe is, as already shown, so 
 wide as to assume commanding importance, and everywhere 
 deserves more attention than we at first gave it. f 
 
 This characteristic of the movement of glacial ice is illus- 
 trated by another phenomenon which has not been sufficiently 
 
 * See " Second Geological Survey of Pennsylyaikia, Z," pp. 46, 206 et stq. 
 + Sec above, p. 149. 
 
GLACIAL EROSION AND TRANSPORTATION. 235 
 
 weighed. In most of the text-books the formation of ice- 
 bergs is represented to be by the pushing out of the ice into 
 the water until the depth is such as to overcome its specific 
 gravity, and lift a mass of ice up bodily and float it away. 
 An inference from imperfect data by Dr. Kane has doubt- 
 less done much to foster this idea. 
 
 Regarded upon a large scale, I am satisfied that the iceberg 
 is not disengaged by debdcle, as I once supposed. So far from 
 falling into the sea, broken by its weight from the parent- 
 glacier, it rises from the sea. The process is at once gradual 
 and comparatively quiet. The idea of icebergs being dis- 
 charged, so universal among systematic writers and so recently 
 admitted by myself, seems to me now at variance with the 
 regulated and progressive action of Nature. Developed by 
 such a process, the thousands of bergs which throng these seas 
 should' keep the air and water in perpetual commotion, one 
 fearful succession of explosive detonations and propagated 
 waves. But it is only the lesser masses falling into deep 
 waters which could justify the popular opinion. The enor- 
 mous masses of the great glacier are propelled, step by step 
 and year by year, until, reaching water capable of supporting 
 them, they are floated off, to be lost in the temperature of 
 other regions.* 
 
 Doubtless some icebergs are thus formed. But any tour- 
 ist to Alaska may now satisfy himself that the ordinary 
 method of the formation of an iceberg is by the breaking off 
 of masses from the top as that portion of the ice is pushed 
 on in advance of the lower strata. Still, as the fractures 
 ivould not always reach to the bottom of a deep inlet, masses 
 thus left below the water would eventually rise to the sur- 
 face in case the front of the ice were retreating, so as to 
 remove the superincumbent weight from them. 
 
 Coming now to consider the direct action of glacial ice 
 in the transportation of solid material, we speak first of that 
 carried upon the surface. Apparently there is scarcely any 
 
 * " Arctic Explorations," vol. ii, p. 148. 
 
236 
 
 THE ICE AGE IX NORTH AMERICA. 
 
 limit to the size of the fragments of rock which can be 
 transported upon the back of a glacier. JSfor would there 
 seem to be any definable limit to the distance tlirough which 
 these masses of rock can thus be carried, except as there is a 
 limit to the movement of the ice itself. In walking out on 
 the smooth surface of the eastern part of the Muir Glacier, 
 it was not uncommon to encounter, miles awaj from any 
 mountains, cubical blocks of stone as much as twenty feet 
 in their several dimensions, which, with countless others of 
 smaller size, united to form a medial moraine. Slowly but 
 surely these great bowlders have been brought to their pres- 
 ent position, and slowly but as surely they are moving on to 
 the front of the glacier, where, in due time, they will be 
 deposited in the terminal moraine. 
 
 Fig. 72.— "Vessel Rock, a glacial bowlder in Gilsum, N. H. (C. H. Hitchcock.) 
 
 The summary of facts published by President Hitch- 
 cock many years ago may fitly serve as an introduction to 
 the more detailed account to follow. In this, after remark- 
 ing upon the great size of single bowlders, he illustrates the 
 remark by the following examples : 
 
 The block called Pierre a Bot, near Neufchdtel, contains 
 40,000 cubic feet. It has been transported from near Mar- 
 tigny, more than sixty miles, across the great valley of Switz- 
 
GLACIAL EROSION AND TBANSPOBTATION. 237 
 
 erland. Professor Forbes describes another bowlder in the 
 Alps, one hundred feet long and forty to fifty feet high ; also 
 another, sixty-two feet in diameter, containing 344,000 cubic 
 feet. In this country bowlders occur of equal dimensions. 
 Thus, on Cape Ann and its vicinity, I have not unfrequently 
 met with blocks of syenite not less than thirty feet in diame- 
 ter ; and in the southeast part of Bradford (Mass.) I noticed 
 one thirty feet square, which contains 37,000 cubic feet, and 
 weighs not less than 3,310 tons. In the west part of Sand- 
 wich, on Cape Cod, I have seen many bowlders of granitic 
 gneiss twenty feet in diameter, which contain 8,000 cubic feet, 
 and weigh as much as 680 tons. Two sandstone bowlders of 
 the same size lie a few rods distant from the meeting-house in 
 Norton. A granite bowlder of equal dimensions lies about half 
 a mile southeast of the meeting-house in Warwick ; and one of 
 similar dimensions lies on the western slope of Hoosac Mountain, 
 in the northeast part of Adams, at least one thousand feet above 
 the valley over which it must have been transported. One of 
 gi'anite lies at the foot of the cliffs at Gay Head, on Martha's 
 Vineyard, which is ninety feet in circumference, and weighs 
 1,447 tons. In Winchester, N. H., I recently met with a block 
 of granite eighty-six feet in circumference. It is near the road 
 leading to Eichmond. I noticed another in Antrim, in that 
 State, one hundred and fifty feet in horizontal circumference. 
 Finally, at Fall Eiver was a bowlder of conglomerate which 
 originally weighed 5,400 tons, or 10,800,000 pounds.* 
 
 A well-known bowlder in eastern Massachusetts, situated 
 on a precipitous cliff in the soutliem part of the town of 
 Peabody, goes by the name of Ship Eock, This is a gran- 
 ite, and measures forty-five feet in length by twenty-two in 
 height, and twenty-five in width. Its estimated weight is 
 1,100 tons, and it is surrounded by many loose fragments 
 weighing from fifty to seventy-five tons each. This rock 
 has been purchased by the Essex Institute of Salem, and is 
 carefully preserved from destruction.f 
 
 * " Elementary Geology," pp. 242, 243. 
 
 •)• See " Journal of Essex County Natural History Society," p. 120. 
 
238 
 
 THE ICE AGE IX XORTH AMERICA. 
 
 In Essex County, Mass., numerous Ijowlders are traced 
 to the White ^Mountain region more than one hundred miles 
 distant. Plymouth Rock is a bo^vkler wliich accomplished 
 its pilgrimage long before the voyage of the Mayflower. The 
 backbone of Long Island largely consists of morainic material 
 torn from the rocky hills of Rhode Island, Connecticut, 
 and Massachusetts. The ".Judge's Cave" on West Rock in 
 New Haven, 365 feet above the sea, is a bowlder weighing 
 a thousand tons. 
 
 Fir,. 73— Mohegan Rock. 
 
 The largest bowlder yet described in New England is 
 Mohegan Rock, in the town of Montville, New London 
 County, Conn. Its dimensions, as reported to me by Mr. 
 David A. Wells, are as follows: Length of eastern side, 54 
 feet; southern side, 70; western side, 56; northern, 58; 
 maximum height at least 60 feet. The weight has been 
 estimated at 10,000 tons. 
 
 Professor Crosby, however, says that a bowlder in Madi- 
 .son, N. H., is still larger than this. Its dimensions are 30 x 4 x 
 75 which would give 90,000 culiic feet and an estimated wei,a:ht 
 
GLACIAL EROSION AND TRANSPORTATION. 239 
 
 of 8,000 tons. But both these must give place to one men- 
 tioned by Professor Edward Orton at Oregonia in Warren 
 County, Ohio, where a mass of Clinton limestone covering 
 three-quarters of an acre, and twenty feet in thickness, has 
 been moved by ice several miles and left with glacial deposits 
 both above and below it. These, however, are small compared 
 with a mass of chalk described by Professor Hoist near Malmo 
 in southern Sweden which is three miles long, one thousand 
 feet wide and from one hundred to two hundred feet in thick- 
 ness, and which has been transported an indefinite distance 
 by glacial ice and left on the surface of ordinary deposits of 
 till. This mass is extensively quarried for commerical pur- 
 poses. The quarries show that the chalk, especially in its 
 upper portions is much disturbed, being broken into small 
 fragments. Even the flint nodules are generally cracked, 
 but the mass as a whole is well defined. A similar transported 
 mass of chalk is reported from the eastern shore of England 
 upon which a village had unwittingly been built. 
 
 The train of bowlders in Richmond, Mass., near the sum- 
 mit of the Berkshire Hills, was long ago described by Presi- 
 dent Hitchcock and Sir Charles Lyell, and more recently 
 and accurately by Mr. E. E. Benton. ^ So much has been 
 written about this train of bowlders, that it is worth while to 
 give the results of this later investigation. The locality is in 
 the towns of Lebanon, N. Y., and Richmond, Lenox, and 
 Stockbridge, Mass., upon the western side of the Berkshire 
 Hills. The trend of the rocky strata here is nearly northeast 
 by southwest, and the elevation of summits of the ridges 
 about sixteen hundred feet above tide, the valleys being 
 about six hundred feet lower. Beginning on the Canaan and 
 Lebanon ridge in New York, there is a line of peculiar bowl- 
 
 * " Geology of New York," Part IV, p. 166, et seq. 
 
 f "American Journal of Science," vol. cxxvi, 1883, p. 34T. 
 
 X LyoU's " Antiquity of Man," pp. 35.')-362 ; " Bulletin of Museum of Com- 
 parative Zoology at Harvard College," Cambridge, Mass., vol. v, No. Ill, p. 41, 
 with map. 
 
240 TEE ICE AOE IN NORTH AMERICA. 
 
 ders about four hundred feet wide, running continuously for 
 nine miles southeast. These bowlders are composed of a 
 ehloritic schist, whose only outcrop is at Fry's Hill, on the 
 summit of the Lebanon range. West of the ridge there are 
 none of these bowlders, but east of the knob the train is con- 
 tinuous. Near the knob the size of the bowlders is larger 
 than at a distance from it. Indeed, the size gradually dimin- 
 ishes as the distance increases. The bowlders are distributed 
 equally over the valleys intervening and over the flanks and 
 summits of the ridges crossed. Besides the main continuous 
 train of bowlders there are three others more or less continu- 
 ous for a part of the way, and originating near the same 
 knob. The diameter of the bowlders varies from thirty feet 
 near their origin, to an average of two feet in Stockbridge, 
 nine miles away. In the vicinity are other bowlders from a 
 ledge whose outcrop was from four hundred to eight hun- 
 dred feet lower than the hills upon which they are now 
 resting. 
 
 Sir Charles Lyell's explanation of these remarkable trains 
 of bowlders was that they were deposited when the region 
 was depressed, so that oceanic currents carried icebergs over 
 the summits of the intervening range, dropping their burdens 
 along on the way. But it is surprising that the bnrdens of 
 the icebergs should have been deposited so regularly, and still 
 more surprising that icebergs should have raised bowlders 
 and deposited them on surfaces eight hundred feet higher 
 than the ledges from which they were torn. This is one of 
 those numerous cases where the glacial hypothesis easily 
 explains all the facts, and where it is difficult to see how 
 any other hypothesis can do so. 
 
 The only really peculiar thing about these celebrated trains 
 of bowlders is that in their case the peak from which they 
 are derived is isolated so that their origin can be readily 
 traced. The prevailing rocks of this region are of such a 
 nature that large bowlders could not readily be formed from 
 tliem, whereas over most of the glaciated region the bowl- 
 ders are so abundant and from such a varietv of localities 
 
GLACIAL EROSIOR AND TRANSPORTATION. 241 
 
 that It is not easy to single out a particular train. Careful 
 attention, however, will doubtless resolve the whole mass of 
 till into confluent trains of bowlders and more finely com- 
 minuted material. 
 
 In New Jersey, according to Professor Cook, the bowl- 
 ders are readily traced all along the morainic margin as be- 
 longing to well-known outcrops of trap, blue limestone, and 
 crystalline rocks to the northwest. Near Drakestown, in 
 Morris county, there is a mass of blue limestone which had 
 been worked for years as a quarry without suspecting that it 
 was but a bowlder. " As exposed it measures thirty-six by 
 thirty feet, and the quarrying has gone twenty feet in depth. 
 Its vertical diameter is unknown. Around it are many 
 gneissic bowlders and other drift materials." * This mass is 
 about one thousand feet above the sea-level, and its native 
 place must have been some miles to the northwest. 
 
 In Pennsylvania the distance from which the glacial ma- 
 terial near the border of the glaciated region has been trans- 
 ported becomes at once more evident, because of its unlike- 
 ness to the local rocks. West of the Kittatinny Mountain, 
 there are no crystalline rocks within the State. Nor are 
 there any to the north nearer than the Adirondacks in New 
 York, or the highlands in Canada. Yet granitic, gneissoid, 
 and hornblendic bowlders abound all along the glaciated 
 border, and are an important means of determining the 
 glacial limit. In the valley between Kittatinny and Pocono 
 Mountains, in Monroe county, and on the summit of the 
 Pocono plateau, 2,000 feet above the sea, granitic bowlders 
 from one to three feet in diameter are abundant, though 
 mingled with great piles of local fragments. The granite 
 must have been transported a distance of 250 miles at least, 
 and carried over the summits of the Alleghanies, intervening 
 toward the northwest, and across the valley of the Mohawk 
 in New York. The northern tributaries of the West Branch 
 of the Susquehanna, likewise, bring down into that stream 
 
 * New Jersey Report for 1 880. 
 
242 THE ICE AGE IN NORTH AMERICA. 
 
 numerous granitic pebbles, showing that glacial deposits in 
 Lycoming county contain material from the far north which 
 has been carried bodily over the summit of the AUeghanies. 
 On proceeding west, the granitic outcrops from which the ma- 
 terial could come, gradually recede to the north, thus increas- 
 ing the distance between such bowlders and their nearest 
 known source. From Salamanca, JS. Y., south westward to 
 Cincinnati the whole country is Uterally covered, down to 
 the glacial limit, with granitic, gneissoid, and hornblendic 
 bowlders. Near Salamanca such bowlders abound at eleva- 
 tions not far from 1,900 feet above tide, and 700 feet above 
 the Alleghany River. In Beaver county they are numerous 
 on the hills down to within six or seven miles of the Ohio 
 River, and several hundred feet above it. 
 
 The following are some of the more specific facts drawn 
 from my own notes : In Colimibiana county, Ohio, a granitic 
 bowlder was found measuring thirteen by eleven feet, and 
 eight feet out of the ground. Others near by were noted, 
 measuring eight and five feet in diameter. In the same 
 vicinity the till contains finely striated fragments of local 
 sandstone, showing direct glacial action on the local rocks. 
 In Holmes county, also, finely polished and striated pebbles 
 of comiferous limestone occur, mingled with fragments of 
 granite in the till. These must have been brought from the 
 other side of the water-shed, in the vicinity of Lake Erie, 
 100 miles distant. Near Lancaster, in Fairfield coimty, there 
 is a granitic bowlder measuring eighteen feet by eleven, and 
 six feet out of the ground. In Ross county, near Adelphi, 
 Chillicothe, and Bainbridge, numerous granitic bowlders were 
 found on the hills from 400 to 600 feet above the valleys, and 
 about 1,200 feet above tide. A hornblendic bowlder five by 
 three by two feet was noted 550 feet above Bainbridge. In 
 Brown, Clermont, and Hamilton counties large granitic bowl- 
 ders abound on the hills down to the very northern edge of the 
 trough of the Ohio. Here, also, are to be found numerous 
 bowlders of jasper conglomerate from the region north of 
 Lake Huron or near the lower end of Lake Superior. The 
 
GLACIAL EROSION AND TRANSPOBTATION. 243 
 
 variegated pebbles of red jasper and of darker quartzites are 
 a striking feature in the rocks of that northern region. The 
 bowlders of this material found in the vicinity must have 
 been transported nearly 600 miles. Several bowlders of this 
 description were found in Boone county, Ky., a number of 
 miles south of the Ohio Kiver and between 500 and 600 
 feet above it. Bowlders of this jasper conglomerate are very 
 abundant in Michigan, are not infrequent in northern Ohio, 
 and occur in various localities in southern Indiana — one 
 being observed near Nashville, Brown county, Ind., near 
 the highest land in the State (about 1,100 feet). Granitic 
 and homblendic bowlders are very abundant, also, as far 
 south as Carbondale, Jackson coxmty, 111., below latitude 38°. 
 The surface rocks are here distinctly striated, and the trans- 
 portation must have been independent of any conceivable cur- 
 rent of water. The distance from this point to the parent 
 ledges to the north can not be less than 600 miles. 
 
 All over northern Missouri, the whole of Iowa, and east- 
 em Dakota bowlders of large size are of frequent occurrence. 
 In some places they completely cover the ground, especially 
 in the Hues of the great moraines. Even west of the Mis- 
 souri, for thirty miles beyond Fort Yates, granitic bowlders 
 are so abundant as to be prominent features in the landscape. 
 Farther north in the same Territory and in Montana they are 
 reported as sometimes so thick that a person can walk for 
 long distances upon them without touching the ground. 
 
 As has been already remarked, the glacial movement was 
 everywhere at right angles to the glacial boundary. We 
 should expect, therefore, to tind that the bowlders along the 
 western border of the glaciated area beyond the Missouri 
 River had been transported from the northeast, and such is 
 undoubtedly the fact. In the recent excui-sion (in 1888) 
 through nortbern Nebraska and central Dakota, already re- 
 ferred to,* I had abundant occasion to see evidences of this 
 transportation. On the hills in Nebraska, from 500 to 600 
 
 * See above, p. 174. 
 
244 THE WE AOE IN NORTH AMERICA. 
 
 feet above the Missouri River, extending in a southwest direc- 
 tion from Yankton, Dakota, to the glacial border, a distance 
 of about forty miles, transported bowlders of considerable 
 size are abundant, and among them are numerous specimens 
 of the so-called Sioux Falls quartzite, whose nearest outcrop 
 is about forty miles to the northeast. 
 
 All along upon the eastern side of tlie river in Dakota 
 the glaxjial accumulations are on an enormous scale, and the 
 transported bowlders without number; and on crossing the 
 river at Fort Yates, about fifty miles south of Bismarck, 
 granitic bowlders, in numerous instances from three to five 
 feet in diameter, are found resting continuously over a belt 
 of the highlands from 500 to 600 feet above the river, and 
 extending about forty miles to the west, where they suddenly 
 cease. There is granite in the Black Hills, 200 miles to the 
 west, and from that source some pebbles have been brought 
 down the Cheyenne River, which rises in that region. But 
 with this exception, there are no granitic bowlders over the 
 area between the Black Hills and this glacial border just 
 mentioned. The source, therefore, of these bowlders on the 
 west side of the Missouri River, extending from Bismarck 
 to the Nebraska line, must lie somewhere to the northeast. 
 Many of them might well enough have come from the vicin- 
 ity of Lake Superior, a distance of 400 or 500 miles, though 
 possibly some of them originated in more limited outcrops 
 of granite in northern Minnesota. 
 
 In British America, the transportation was outward from 
 the Laurentian axis in every direction. From this axis bowl- 
 ders in immense quantities were carried from 600 to 700 
 miles westward and left on the fianks of the Rocky Mount 
 ains, from 2,000 to 3,000 feet above their source. 
 
 In Dr. George M. Dawson's report upon the extension of 
 the Missouri coteau into the central region of I^orth Amei^ 
 ica, he estimated that nearly ninety-eight per cent of this 
 great accumulation between the Missouri and Saskatchewan 
 Rivers was from the Laurentian axis, some hundreds of miles 
 to the east ; and that, upon the fringe beyond the coteau 
 
OLAGIAL EROSION AND TRANSPORTATION. 2-15 
 
 where there is a mingling of material brought down from 
 the Rocky Mountains, there is still for some distance as 
 much as forty-eight per cent of Laurentian material. 
 
 Still farther north Dr. Dawson reports a movement of 
 bowlders toward the north in the head-waters of the Yukon 
 River, and in the northern portion of the continent east of 
 Mackenzie River. 
 
 For the arctic coast of the continent and the islands of the 
 archipelago off it there is a considerable volume of evidence to 
 show that the main direction of movement of erratics was 
 northward. The most striking facts are those derived from 
 Professor S. Haugh ton's appendix to McClintock's "Voyage," 
 where the occurrence is described of bowlders and pebbles from 
 North Somerset, at localities 100 and 135 miles northeastward 
 and northwestward from their supposed points of origin. Pro- 
 fessor Haughton also states that the east side of King William's 
 Land is strewn with bowlders of gneiss like that of Montreal 
 Island, to the southward, and points out the general north- 
 ward ice-movement thus indicated, referring the carriage of 
 the bowlders to floating ice of the Glacial period. 
 
 The copper said to be picked up in large masses by the 
 Eskimo, near Princes Royal Island, in Prince of Wales Strait, 
 as well as on Prince of Wales Island,* has likewise, in all prob- 
 ability, been derived from the copper-bearing rocks of the Cop- 
 permine River region to the south, as this metal can scarcely 
 be supposed to occur in place in the region of horizontal lime- 
 stone where it is found. 
 
 Dr. A. Armstrong, surgeon and naturalist to the Investi- 
 gator, notes the occurrence of granitic and other crystalline 
 rocks not only on the south shore of Baring Land, but also on 
 the hills at some distance from the shore. Tliese, from what 
 is now known of the region, must be supposed to have come 
 from the continental land to the southward. 
 
 Dr. Bessells, again, remarks on the abundance of bowlders 
 on the shore of Smith Sound in latitude 81° 30', which are 
 manifestly derived from known localities on the Greenland 
 
 * De Eance, in " Nature," vol. xi, p. 492. 
 
246 TEE lOE A GE IN NORTH AMERICA. 
 
 coast much farther southward, and adds, " Drawing a con- 
 clusion from such observations, it becomes evident that the 
 main line of the drift, indicating the direction of its motion, 
 runs from south to north."* 
 
 It may further be mentioned that Dr. E. Bell, of the Cana- 
 dian Geological Survey, has found evidence of a northward or 
 northeastward movement of glacier-ice in the northern part of 
 Hudson Bay, with distinct indications of eastward glaciation 
 in Hudson Strait, f For the 'northern part of the great Mac- 
 kenzie Valley we are as yet without any very definite infor- 
 mation, but Sir J. Richardson notes that Lauren tian bowlders 
 are scattered westward over the nearly horizontal limestones of 
 the district. 
 
 Taken in conjunction with the facts for the more southern 
 portion of the continent, already pretty well known, the ob- 
 servations here outlined would appear to indicate a general 
 movement of ice outward, in all directions, from the great 
 Laurentian axis or plateau which extends from Labrador round 
 the southern extremity of Hudson Bay to the Arctic Sea ; 
 while a second, smaller, though still very important region of 
 dispersion — the Cordilleran glacier-mass — occupied the Rocky 
 Mountain region on the west, with the northern and southern 
 limits before approximately stated.J 
 
 Some facts already mentioned * have prepared the way for 
 the discussion of that most puzzling and interesting problem 
 of the upward transportation of earthy material in moving 
 ice. The evidence upon this point is too abundant to be 
 ignored. Professor Charles H. Hitchcock reports finding near 
 the very summit of Mount Washington many small bowlders 
 which must have been elevated a considerable portion of its en- 
 tire height. One of these bowlders, weighing ninety pounds, 
 is now deposited in the museum of Dartmouth College ; and 
 
 * " Nature," vol. ix. 
 
 t " Annual Report of the Geological Survey," Canada, 1886, p. 14, D. D ; 
 and " Report of Progress," 1882-'84, p. 86, D. D. 
 
 X See " Glaciation of British Columbia," " Geological Magazine," August, 
 1888, pp. 348, 349. 
 
 * See above, pp. 197, 240 
 
GLACIAL EROSION AND TRANaPORTATIOK 247 
 
 another, of equal weight, may be found in the museum of the 
 Boston Society of Natural History.* Professor Hitchcock 
 wriles me that while none of the very large bowlders in New 
 Hampshire have been lifted up very much, it is safe to say 
 that every New England mountain has bowlders on its sum- 
 mit that have been brought there by the ice from at least as 
 great a distance as from its immediate base. 
 
 Describing a cut in till, forty feet deep, near the village 
 of Queechee, Vt., on the Connecticut Eiver, Professor 
 Hitchcock says it is full of small-sized glaciated stones, 
 cemented together by thick bowlder clay. Every stone is 
 striated. There are great numbers of the Burlington (Yt.) 
 red sandstone, "which must have traveled from over the 
 Green Mountains, over sixty miles, and have been raised 
 over an acclivity of 3,000 feet altitude." f 
 
 Professor A. S. Packard, Jr., reports % that, at the height 
 of about 4,000 feet above the sea, on Mount Katahdin, Me., 
 " is a large mass of glacial moraine matter which has escaped 
 denudation, and this incloses frequent rounded and polished 
 bowlders of fossils of the same species of Silurian shells, and 
 of the same silicious slates, as are found in situ a few miles 
 northwest, on Lakes Webster and Telos. . . . The parent 
 beds are but about twelve miles distant," and, according to 
 Mr. Upham, must be 3,000 feet lower. 
 
 One of the clearest instances of the elevation of bowlders 
 in the ice is the one already alluded to, * in the vicinity of 
 the Delaware ' Water-Gap, on the summit of Kittatinny 
 Mountain. This summit consists of Medina sandstone, and 
 is about 1,500 feet above tide. Yet Professor Lewis found 
 numerous bowlders of Helderberg limestone upon it, which 
 he thinks must have come from Godfrey's Eidge, in Cherry 
 Yalley, only a few miles to the north, and 1,200 feet lower. 
 
 * For particulars concerning these bowlders, see Hitchcock, " New Hamp- 
 shire Geological Report," vol. iii, pp. 204, 207, 272. 
 
 f " New Hampshire Geological Report,'' vol. iii, p. 262. 
 
 X " Memoirs of the Boston Society of Natural History,'' vol. i, p. 239. 
 
 * See cut above, p. 196. 
 
248 THE ICE AQM iN NOBTH AMERICA 
 
 Professor Lesley adds his testimony that in all northeastern 
 Pennsylvania there is no other source of these bowlders but 
 the one line of outcrop mentioned by Professor Lewis ; but, 
 as it extends a hundred miles in a northeasterly direction, he 
 is not sure that the particular locality from which these Hel- 
 derberg bowlders came can be determined. Still, he is cer- 
 tain that every limestone bowlder in northern New Jersey 
 and eastern Pennsylvania has come from some point along 
 this line of outcrop. Nowhere, however, does the Helder- 
 berg limestone rise to an elevation of more than 1,000 feet 
 above tide, while some of these bowlders are 1,500 feet 
 above tide. Kemarking upon this. Professor Lesley says : 
 
 The only problem of prime difficulty is, how the ice man- 
 aged to lift the fragments from the outcrop in the valley to 
 the crest of the Kittatinny Mountain — a problem which is re- 
 peatedly presented for our 'olution at various points where the 
 terminal moraine crosses our mountain - ridges, and where 
 blocks from a valley to the north are left perched on a mount- 
 ain-top to the south. And the problem is not confined to the 
 line of the moraine, but repeats itself at points many miles 
 back of the moraine. Twenty years ago I found Catskill red 
 sandstone fragments which had been carried up the north 
 flank of the Towanda Mountain, in Bradford county, and been 
 left on the edge of a swamp upon its flat summit of coal-meas- 
 are sandstone ; and there is no Catskill country to the north 
 'X a higher elevation from which the ice could have brought 
 them with a descending gradient. 
 
 Professor James Hall informs me that fragments from 
 the Mohawk Valley have been carried up over the Hel- 
 derberg Mountain to the south of it, precisely as the Ron- 
 dout-Walkill bowlders have been carried over the Kittatinny 
 Mountain. 
 
 So, judging by the southeast striae, the gneiss and granite 
 bowlders of western Pennsylvania must have been carried up 
 from the level of Lake Erie (570 feet above tide) to elevations 
 of 1,500 feet, along the line of the terminal moraine, 1,700 feet 
 above tide at Lake Chautauqua, and even 3, 150 feet above tide 
 
QLAVIAL EROSION ASD TRAXSPORTATIOX. 249 
 
 in Little Valley, Cattaraugus county, N. Y. ; unless we sup- 
 pose that all the Canadian bowlders were borne upon the sw- 
 face of the ice, which is clearly impossible. 
 
 Bowlders of Alpine glaciers seem always to descend to their 
 final resting-place, but we have innumerable proofs that the 
 American ice-sheet managed, in some way, to carry bowlders 
 from valleys up to mountain-tops, although the amount of 
 elevation in many cases, if not in all cases, may be much less 
 than we are inclined, on a first inspection of the facts, to take 
 for granted. 
 
 In the case of the Helderherg limestone bowlders men- 
 tioned, found by Mr. Lewis on the crest of the Kittatinny 
 Mountain, it is not necessary to suppose that it came from 
 Godfrey's Eidge, only three miles distant (north) in the valley 
 below, 1,000 feet beneath its present position. Indeed, the 
 direction of the scratches on the mountain-side make such a 
 supposition incredible. It is plain that it must have traveled 
 down the valley of the Delaware, and may have come from the 
 continuation of the range in the State of New York. The 
 elevation of the surface gradually increases going east. The 
 rise in the bed of the river for the first thirty-five miles, from 
 the Delaware Water-Gap to Port Jervis, is about 300 feet. 
 The rise from Port Jervis to the Eondout-Walkill divide, 
 •twenty miles, is 80 feet more. There the crest of the Helder- 
 herg Eidge must be nearly 1,000 feet above tide. The crest of 
 the Kittatinny Mountain where the block lies is about 1,500 
 feet above tide. Therefore, if the block came these sixty-five 
 miles, it has been carried up only 500 feet above its original 
 situation. 
 
 Still, it remains a problem by what sort of internal move- 
 ment a stone held in the ice can ascend, however gentle may 
 be the gradient upward. That internal movements take place 
 in all glaciers, is made visible to the spectator by their spoon- 
 shaped stratification, and by the different rates at which their 
 upper, lower, middle, and lateral parts move along, as well as 
 by the fact that they press forward over rock-barriers. But 
 so general a statement has no scientific value when evoked to 
 explain the actual translation of a bowlder up a mountain- 
 slope. In fact, our knowledge of how such an operation was 
 
250 THE ICE AGE IN NORTH AMERICA. 
 
 performed is as vague as possible, and demands the attention 
 of hydraulic engineers.* 
 
 Elsewhere f I have briefly considered the way in which 
 this upward movement of bowlders imbedded in the. glacial 
 current might be produced. The subject is of so much in- 
 terest and importance that it will be well to recur to it here. 
 
 As a result of the differential motion in a glacier in which 
 each higher stratum of ice is moving slightly faster than that 
 which is immediately below it, it follows that the inclosed 
 bowlders are subjected to a differential strain, in w^hich the 
 upper portions are impelled forward with greater rapidity 
 than the lower portions. The result of this differential strain 
 upon the upper and lower portions of the bowlder, combined 
 with the friction and viscosity of the ice, must produce a 
 movement slightly upward as well as forward. The bowlder, 
 being inelastic, or at any rate less elastic than the ice in 
 which it is imbedded, must move as one mass, while each 
 particle of ice moves in iudependence of all the others. 
 Now, the portion of ice lying immediately in front of a 
 bowlder, being protected from the differential pressure of 
 the ice behind by the interference of the inelastic foreign 
 object, offers more resistance in that direction than is pre- 
 sented along a line leading diagonally upward across the lines 
 of greater movement above. In other words, the frictional 
 pressure of the moving ice upon the upper portion of a bowl- 
 der is greater than that on its lower portions, and the greatest 
 of all resistance is immediately in front. The line of least 
 resistance is consequently always in a direction slightly up- 
 ward. If, for example, the movement of the ice at the upper 
 surface of a bowlder be represented by 100, and that at the 
 lower portion of the bowlder by 99, then one one-hundredth 
 of the force might be supposed to be expended in producing 
 a diagonal upward movement. Thus we can conceive that 
 fragments of rock were picked up from beneath the glacier, 
 
 * See " Second Geological Survey of Pennsylvania, Z," p. xxiii et seq. 
 f "Glacial Boundary in Ohio, Indiana, and Kentucky," p. 31. 
 
QLAOIAL EROSION AND TRANSPORTATION. 251 
 
 and that, after moving a STifficient distance, they appeared 
 upon its surface ; and we can easily believe that many bowl- 
 ders have thus been repeatedly transferred from beneath the 
 ice to its surface, and thence projected by the more rapid 
 superficial motion to the front to be reincorporated into the 
 lower strata of the mass, and re-elevated to the surface again. 
 Upon this subject Professor Lesley ofEers the following 
 ingenious suggestions : 
 
 When two equal solid bodies descending opposite slopes 
 meet, they arrest and support each other. 
 
 Imagine myriads of cannon-balls rolled from both sides to 
 meet in the middle of a symmetrical valley. Those arriving 
 first would remain ever afterward the lowest stratum ; those 
 which followed would arrange themselves in higher and higher 
 layers until the valley was full or the supply exhausted. No 
 shifting of places would take place after each had' found its 
 lowest place. 
 
 But suppose opposite descending quantities of pitch, or 
 moist clay, through which cannon-balls were scattered, to meet 
 along the middle line of a valley ; the two advancing fronts 
 would mash against each other, and thicken upward, the in- 
 cluded cannon-balls rising vertically' in the thickening mass, 
 the thickening being in proportion to the height and weight 
 and rigidity of the masses of clay pressing from the side slopes 
 upon the middle line which had come to rest. 
 
 By substituting plastic ice for moist clay, and rock-bowlders 
 for cannon-balls, we get an idea of how the American ice-sheet 
 may have carried up (diagonally) the masses which it tore 
 from low-lying outcrops to higher levels, and even over mount- 
 ain-crests. . . . 
 
 A terminal moraine is often described as if it were merely 
 the tumbled-off accumulation of the medial and lateral mo- 
 raines which cover the surface and sides of a glacier. But the 
 fact is, that a glacier is like a plum-pudding— full of scattered 
 sand and stones from top to bottom and from side to side, all 
 of which are delivered at its front end down the valley. The 
 surface exhibition is made much stronger than it would other- 
 . wise be by the perpetual melting of the upper surface and sides 
 
256 THE lOE A6E IN NORTH AMERICA. 
 
 showed that the quantity of mud varied in the difEerent streams, 
 and even in the same river. The result of ten different obser- 
 vations in the months of June and July gave a mean of 147-9 
 p-ammes of mud in 1 cubic metre of water. (See " Quarterly 
 Journal of the Geological Society," 1877, p. 157.) * 
 
 Mr. J. E. Marr gives the following facts concerning the 
 extent to which erosion is proceeding beneath some of the 
 Greenland glaciers : 
 
 The erosive power of an ice-sheet is well seen by a glance 
 at the observations made upon the rivers which flow into the 
 fiords of Nagsugtok and Isortok, and which have -their origin 
 at the ends of the tongues of ice which occupy the val- 
 leys continuous with these fiords. The river from the first 
 contained only 200 to 325 grammes of mud per cubic metre of 
 water in the month of July ; while the second, in the month 
 of June, inclosed 9,129 to 9,744 grammes. This is compared 
 with the amount carried by the Aar where it emerges from 
 the glacier ; it there contains only 142 grammes. The great 
 difference presented by the rivers which fall into the two fiords 
 is attributed to the fact that the ice moves with much greater 
 speed toward the fiord of Isortok than toward that of Nagsug- 
 tok. It is calculated that the quantity of fine mud carried 
 into the former of these fiords amounts to 4,062,000,000 kilo- 
 grammes per day. This mud is deposited in the interior of 
 the fiord, which is filled up to such an extent in its upper por- 
 tion that even flat-boats can not pass up it.f 
 
 The amount of material carried to the sea by the subgla- 
 cial streams during the continuance of the Glacial period 
 in North America could not be estimated, even though we 
 knew the rate of transportation, unless we had more definite 
 ideas than we now have of the length of time during which 
 glacial conditions prevailed. But if, as is probably the case, 
 the deposits of loess in the valley of the Mississippi are of 
 
 * Geikie's " Prehistoric Europe," pp. 231, 232. 
 
 f See " Geoloji^cal Magazine," April, 1887, summarized in " American Jour- 
 nal of Science," vol. czxxiv, 1887, p. 313. 
 
GLAOIAL EROSION AND TRANSPORTATION. 257 
 
 glacial origin, these may at some time give us a partial clew 
 to the length of the period. 
 
 Another method of estimating the amount of glacial ero- 
 sion is by calculating the extent of the deposits over the 
 glaciated region. Professor Newberry has estimated that 
 the area south and west of the Canadian highlands, covered 
 with glacial debi^is, is not much less than 1,000,000 square 
 miles, and that the depth of the deposit over this broad 
 marginal area can not be less, on the average, than thirty 
 feet, and is probably twice that amount.* Professor Glaypole 
 found, upon comparing the estimates independently made 
 in different counties of Ohio, Indiana, and Illinois, that the 
 average depth for these three States was sixty-two feet, and 
 
 Fig. 76. — Ideal section showing how the till overlies the stratified rocks. 
 
 for Ohio alone fifty-six feet.f Kecent extended experi- 
 ments in boring for gas in western Ohio and eastern Indi- 
 ana tend greatly to increase the estimate of Professor Clay- 
 pole. There are whole counties in southwestern Ohio so 
 deeply covered with glacial debris, that few of the citizens 
 have ever seen the underlying rock. In other counties, 
 where the rock occasionally crops out at the surface, the ex- 
 tensive spaces between are found to be valleys of immense 
 depth, filled with the unstratified material of the ground 
 moraine. In Professor Orton's recent report on the subject, 
 giving the depth in fifty-three of the counties of Ohio as 
 determined by the borings in 122 wells, the average is found 
 to be upward of 90 feet (93 feet -(-). In some of the wells 
 the depth was truly phenomenal, as in St. Paris, Champaign 
 county, where, in one well, rock was not reached short of 
 
 • "School of Mines Quarterly," January, 1885, p. 7. 
 
 f " Glacial Erosion," by William M. Davis, " Proceedings of the Boston 
 Society of Natural History," vol. xxii, pp. 19-58. 
 
258 THE ICE AGE IN NORTE AMERICA. 
 
 370 feet, and in another, 530 feet of till was penetrated, and 
 the well abandoned before rock was reached. In Dayton, 
 Montgomery county, the glacial deposit was found to be 247 
 feet; in Cridersville, Aaglaize county, 300 feet; in New- 
 ark, Licking county, 235 feet ; in Lebanon, Warren county, 
 256 feet ; in Osborn, Greene county, 207 feet ; in Hamilton, 
 Butler county, 214 feet. These are all, perhaps, in pre- 
 glacial valleys. But the average in various counties is cer- 
 tainly significant. In Auglaize county, six borings give an 
 average of 141 feet; in Butler county, four borings, 116 
 feet. 
 
 "With reference to the correctness of this representation, 
 it should be remarked that borings prosecuted in this man- 
 ner are more likely to give an underestimate than an over- 
 estimate of the real facts ; for, as is well known, it is much 
 easier and less expensive to drill through the sedimentary 
 rocks than through deep deposits of till and looser drift; 
 so that the aim of the prospectors is to begin their wells at 
 points where the rock will be reached at as small a depth as 
 possible. But so completely have the pre-glacial lines of 
 erosion been obliterated in many places in Ohio, that it is 
 impossible to calculate the proximity of the rock to the sur- 
 face. Where the deepest drift was penetrated (530 feet in 
 Champaign county), special effort was made to locate the 
 boring where the superficial deposits were shallow; but, as 
 the result proved, the surface indications were deceptive and 
 a serious mistake was made, involving the contractor in great 
 loss. It should, however, be observed that the deep well 
 at St. Paris lies in the line of one of the great terminal 
 moraines traced by Mr. Leverett across central Ohio, and 
 where the depth of the glacial deposits is supposed to be 
 excessive even in a moraine. 
 
 Mr. Upham estimates the mantle of drift that conceals 
 the rocks in central Minnesota to be between 100 and 200 
 feet deep. In the Eed River region, to the north, and over 
 a wide belt stretching many hundred miles along the flanks 
 of the Rocky Mountains, in the Dominion of Canada, the 
 
OLAQIAL EROSION AND TRANSPORTATION. 259 
 
 depth is equally great. In the upper valley of the South 
 Saskatchewan, at an elevation of about 4,000 feet above the 
 sea, and from 600 to YOO miles west of the Laurentian axis, 
 from which much of the glaciated material came, Mr. McCon- 
 nell reports sections of till 125 feet deep.* 
 
 Professor Stone thinks the average thickness of the drift 
 in Maine is between thirty and fifty feet. Mr. TJpham's 
 early calculations for New Hampshire were much more mod- 
 erate, namely, ten feet.f But he now informs me that he 
 would make a much higher estimate. Besides, in so mount- 
 ainous a district, we should expect a thinner deposit to re- 
 main on the surface. The more rapid streams would trans- 
 port a larger portion of the material to the sea than from the 
 gentle slopes. Furthermore, the rocks of New Hampshire 
 are better calculated to resist erosion than in some other por- 
 tions of the country. Much of the soil of New Hampshire 
 has been transported to the States farther south. No re- 
 liable estimate lias been made of the average depth of 
 the glacial accumulations over Massachusetts, Connecticut, 
 and lihode Island. There can be little doubt, however, that 
 it is much greater than Mr. Upham makes for New Hamp-, 
 shire. 
 
 Professor Shaler X sets down the total amount of drift in 
 New England and its neighboring terminal moraines at 750 
 cubic miles, or more than the mass of the White Mountains. 
 If evenly distributed, this would make a layer of about sixty- 
 five feet. 
 
 Professor Lesley says the depth of the glacial drift over 
 the northeastern counties of Pennsylvania is not less than 
 fifty feet. This is on the summit of the Appalachian plateau, 
 while the old valleys, filled with glacial debris, are some of 
 them of great depth. One on Mehoopany Creek, in "Wyo- 
 ming county, is filled with drift to a depth of more than 235 
 
 * " Report of the Cypress Hills," 1886. 
 
 f " New Hampshire Geological Report," vol. iii, p. 293 
 
 X " Illustrations of the Earth's Surface : Glaciers," p. 58 
 
260 THE ICE AGE IN SOUTH AMERICA. 
 
 feet. In this vicinity, Professor I. C. White * reports wells 
 fifty feet deep which barely reach through the till, and this 
 on elevations 1,335 feet above tide. 
 
 Great as these amounts may seem, the estimation of the 
 erosion in the Scandinavian Peninsula by Professor Holland 
 is still larger.f Holland, after conference with several 
 geologists familiar with the region, estimates that the aver- 
 age depth of the drift over north Germany and northwest 
 Russia is 150 German feet. This would indicate that the 
 erosion from the Scandinavian Peninsula had been as much 
 as 250 feet, since the material has nearly all been derived 
 from Scandinavia, and the area of the source of supply in 
 Scandinavia is only two fifths of that over which it was dis- 
 tributed. 
 
 This estimate of Holland for Scandinavia is not, how- 
 ever, greater than that of Professor Lewis for northern 
 Pennsylvania. Here, on the Kittatinny Mountain, near the 
 Delaware Water-Gap, this observer seems to have had a 
 rare opportunity for directly measuring the eroding power 
 of the ice at that point.:]: The summit of the mountain is 
 crowned by compact strata of Medina sandstone, and trends 
 northeast by southwest. The glacier surmounted the ridge 
 on both sides of the Water-Gap, and extended twelve or 
 fitfteen miles farther south, while to the southwest the sum- 
 mit of the mountain was outside of the line of ice-movement, 
 which just here is bordered by cHfEs of the crowning Medina 
 sandstone seventy feet high, as if the ice, in moving past 
 them, had worn down the strata underneath to that amount. 
 Professor Lesley, at the Minneapolis meeting of the Ameri- 
 can Association for the Advancement of Science, in 1884, 
 took this as a measure of glacial erosion to illustrate how 
 
 " See " Second Geological Survey of Pennsylvania on Wyoming, Lackawanna, 
 Luzerne, Columbia, Montour, and Northumberland Counties G'," p. xili. 
 
 f " TJeber die Glacialen Bildungen der nordeuropaiscben Ebene, Deutsch. 
 Geol. Gesell.," Zft. xxxi, 1879, p. 97. 
 
 t " Second Geological Survey of Pennsylvania Z," pp. 70, 90. See also 
 above, p. 196. 
 
GLACIAL EROSION AND TRANSPORTATION. 261 
 
 small it was. But Professor Newberry well replied that, if 
 there was that amount of erosion so near the margin, what 
 must it not have been farther back, where the stream of ice 
 had acted for an indefinitely longer time. Probably, how- 
 ever, Newberry is extravagant when he estimates that farther 
 north the ice was ten times as thick, and continued to act 
 ten times as long, making its erosive power one hundred 
 times as great as that near the "Water-Gap.* 
 
 The foregoing evidence of glacial erosion drawn from 
 the extent of marginal glaciM deposits is complicated by our 
 ignorance of the extent to which disintegration of the rocks 
 had proceeded before the Glacial period. Professor Whit- 
 ney f and Mr. PumpeUy | have specially pressed this point, 
 as have Professor Sterry Hunt and the late Mr. L. S. Bur- 
 bank,* to whom more credit is due than he has generally 
 received for his early and sagacious suggestions upon the 
 subject. The contrast between the glaciated and the un- 
 
 PiG. 77.— Ideal section showing result of disintegration in an unglaciated region. 
 (Chamberlin.) 
 
 glaciated region, in the extent to which the surface rocks are 
 disintegrated by subaerial agencies, is very striking. South 
 of the glaciated region granitic masses and strata of gneiss 
 
 * " School of Mines Quarterly," p. 12, 
 f " Climatic Changes," p. 7 et acq. 
 
 X " The Relation of Secular Kock-Disintegi'ation to Loess, Glacial Drift, and 
 Rook Basins," in the "American Journal of Science," vol. cxvii, 1879, p. 133 
 et «eq. 
 
 * " On the Formation of Bowlders and the Origin of Drift Material," in 
 the " Proceedings of the Boston Society of Natural History," vol. xvi, Novem- 
 ber 19, 1873. 
 
262 THE ICE AGE JN NORTH AMERIOA. 
 
 are often completely disintegrated to a great depth, some- 
 times amounting to scores of feet. What seem like beds of 
 gravel (and which can be handled with a shovel) often prove 
 to be horizontal strata of gneiss from which the cementing 
 material has been removed by the slow action of percolating 
 acids brought down by the rains. North of the glacial 
 boundary it is very rare to find any such extensive evidence 
 of disintegrating agencies. Since the ice passed over this 
 region there has not been suflBcient time for subaerial agen- 
 cies to produce any marked disintegrating effect. 
 
 Now, it is with much plausibility contended that the 
 action of the ice has been limited chiefly to the trcmsporta-, 
 tion of this disintegrated material, and that it has had little 
 effect as an eroding agency. The strong point in this repre- 
 sentation is, that there is little more loose soil over the 
 margin of the glaciated region than would result from the 
 simple transportation of the disintegrated material from the 
 northern and central portions of the glaciated region to the 
 marginal area. It certainly is clear, both from the necessities 
 of the case and from actual observation, that the area of 
 greatest erosion is nearest the center from which the ice 
 radiated, and that, as the amount of deposition increased 
 toward the margin, the erosion diminished. 
 
 The advocates of the great erosive power of glacial ice 
 appeal, also, to the general appearance of the glaciated sur- 
 faces wherever exposed. The islands near Sandusky, in the 
 western part of Lake Erie, for example, present some of the 
 most marked indications of glacial erosion anywhere to be 
 found, and the facts there ai-e justly appealed to by Professor 
 Newberry in support of the theory that the ice was a promi- 
 nent agent in the formation of the basins of the Great 
 Lakes. 
 
 As this is so important a region for glacia,l study, I will 
 give somewhat in detail the result of my own recent obser- 
 vations. There are twelve or fifteen islands near the west- 
 ern end of Lake Erie, of which Kelly's, North Bass, Middle 
 Bass, South Bass, and Pelee ai-e the principal, each having 
 
GLACIAL EROSION AND TRANSPORTATION. 263 
 
 an area of several square miles, and none of them rising 100 
 feet above the surface of the lake. They all consist of the 
 hard limestones of the Niagara series. In every instance, as 
 one approaches them from the eastern side, his attention is 
 atti-acted by tlie remarkaljle depth and continuity of the 
 glacial grooves running nearly east and west upon tliem, and 
 which rise out of the water, and continue to the summit of 
 the islands, or until they are covered by the ground moraine 
 which has not been washed away by the waves. In some 
 
 Fig. 78. — Glacial grooves on east sidy of South Ba^8 iHlaiid, Laice Elk-, rimiiiiig west 10^ 
 
 south. 
 
 instaTices, these grooves are two or three feet deeji, and ex- 
 tend many rods in plain sight. JSTor are they in all cases 
 straight, but sometimes are extremely tortuous, winding along 
 in their course like the channel of a sluggish stream. It is 
 evident, in some cases, that the main features of these deep- 
 est grooves liave been determined by preglacial or subglacial 
 water-action, and that the ice, or tlie ground moraine under 
 
Fig 79.-Tortuous grooTes ou Kdly's l^lan.l. l.ak^' Erie. United States Ueologital 
 Survey ^Chamberliii). 
 
GLACIAL EROSION AND TRANSPORTATION. 265 
 
 the ice, has moved along in a previously foraied mold, 
 scouring it out and polishing it, and somewhat enlarging it. 
 Thus it comes about that sometimes even the under surface 
 of a projecting rock has been scratched and poHshed by the 
 ice-movement. In case of the shallower grooves, two or 
 three inches or less in depth, the abrupt variations are numer- 
 ous, as if a pebble had encountered an obstacle to its direct 
 movement, and. turned aside to move onward in a new line 
 of least resistance, the general course remaining substantially 
 the same. 
 
 That there has been here considerable erosion by direct 
 action of the ice there can be no doubt ; but that it is less 
 than some suppose is perhaps shown from the cross-striae, 
 which indicate four distinct but successive movements. The 
 course of events was plainly as follows : 
 
 1. When the advancing ice filled the vaUey of Lake Erie, 
 but had not surmounted the summit of the water-shed to the 
 south, and before the Illinois lobe of ice had extended across 
 Lake Erie's natural southwestern outlet, the ice-movement 
 in Lake Erie was in the line of the longest diameter of the 
 lake — ^i. e., southwest. 
 
 2. During the height of the Glacial period, when the ice 
 surmounted the water-shed between the lake and the Missis- 
 sippi basin, about one hundred miles to the south and from 
 five to seven hundred feet higher, the movement of the 
 ice was very nearly north by south. There was then no 
 opportunity for the ice to escape from the southwestern end, 
 because of the larger general movement of the glacier across 
 its pathway. So powerful was this movement in a southerly 
 direction that deep north-and-south channels were eroded in 
 all the islands. 
 
 3. But, upon the retreat of the ice to the water-shed, and 
 the withdrawal of the glacier, which crossed its way on the 
 southwest, the former westerly line of movement was at once 
 resumed. Each later movement has done much to obliterate 
 the marks of the earlier. Upon the eastern slopes this oblit- 
 eration is sometimes complete. But wherever there was a 
 
266 THE ICE AGE IN NORTH AMERICA. 
 
 lee side of a prominence in wliicli a north-and-south glaci- 
 ated surface could be protected from the force of the eastern 
 current, we find that it was protected, and the glaciated sur- 
 face is as fresh on the removal of the soil as it is anywhere. 
 In places the beveled edges of earlier grooves are perfectly 
 distinct where the second cross-movement has obliterated a 
 part of a groove, and left still untouched the portion of the 
 earlier groove which was protected by a ridge. Within a 
 half mile of each other there are grooves several inches in 
 depth running at right angles to each other. For instance, 
 upon the west side of Gibraltar (which is a small, rocky island 
 at the mouth of Put-in Bay, close to South Bass Island), there 
 are deep grooves, running north by south, made by the sec- 
 ond movement; bnt they were perfectly protected by the 
 rock, which received the brunt of the third movement as it 
 came from the east. One half mile west, and a little south 
 of this point on the main island, where there is a shallow 
 valley across the island, the east-and-west grooves are equally 
 striking. This was doubtless the movement whose record is 
 left in the moraine of the Maumee Yalley, as already described 
 by Gilbert.* 
 
 4. There were also indications of still a fourth movement, 
 which set in when the ice had receded so far that the obstruc- 
 tion presented by the elevation of the water-shed to the south 
 would no longer compel a westerly movement. But, when 
 the ice-front was between these islands and the south shore, 
 the movement would again be, according to theory, to the 
 south, at right angles to the first and third movements. This 
 last movement, however, was probably feeble and not of long 
 continuance. Still, there are some signs of it in the shape 
 of shallow striae across the second set of east-and-west far- 
 rows. While all this is witness to the efficiency of ice as an 
 eroding agency, it conveys the impression that the erosion 
 accomplished by each successive movement was concentrated 
 in special channels, and was nowhere excessive. 
 
 * See p. 207 
 
GLACIAL EROSION AND TRANSPORTATION. 267 
 
 Fig. 80.— Section of east and we.-t ghiciul t'liiTow;?, on Kell,v'.s Island. Till rests imme- 
 diately on the rock, "with washed pebbles at the surface. 
 
 The following very important extracts concerning glacial 
 erosion, from the recent report of Mr. I. C. Rnssell, need 
 no introduction and no comment : 
 
 That the rock-basins in the high Sierra were excavated by 
 glaciers the writer finds no reason whatever to question. They 
 frequently occur at the lower limit of a steep slope, which is 
 polished and grooved, and bears every indication of having 
 been abraded by glacial action. In such cases the slope and 
 the direction of the furrows show that ice once descended into 
 the basin. On examining the opposite portion of the rim of 
 the depression, glacial markings of the same character will be 
 found. The proof is thus positive that the ice descended into 
 the depressions now filled with water, and emerged from them 
 again to continue its course. As there is no other agent known 
 capable of eroding hollows in solid rock having the character 
 
GLACIAL EROSION AND TRANSPORTATION. 269 
 
 of the basins obsei-ved in the high Sierra, it seems evident that 
 the theory of the formation of rock-basins proposed by A. C. 
 Ramsay, from evidence obtained in Scotland and Switzerland, 
 is substantially correct, and furnishes the true explanation of 
 the origin of the examples before us.* The manner in which 
 the power of moving ice is directed so as to erode depressions 
 may be open to discussion, but the conclusion that rock-basins 
 are a result of glacial action is now too strongly supported by 
 facts to be questioned. . . . 
 
 On examining the numerous lakes more critically, one finds 
 that many of them occupy depressions in morainal debris, or 
 are confined by terminal moraines. In numerous instances, 
 however, as in Bloody and Gibbs Caflons, at the head of Eush 
 Creek, and all about Mount Lyell and Mount Ritter, the fact 
 that the lakes occupy depressions in solid rock is beyond all 
 question. One may walk entirely around many of them with- 
 out stepping off rock in place. ... 
 
 As some writers — especially those who are given to solving 
 the mysteries of Nature from their closets — have thought that 
 lakes filling true rock-basins are a rarity, and have even doubt- 
 ed whether they exist at all, we shall be interested in examin- 
 ing this result of glacial action, while we wait for our mule- 
 train to join us. The streani from above cascades over hun- 
 dreds of feet of rock before reaching the lake ; on either hand 
 the overshadowing cliffs tower upward for a thousand feet ; 
 and we can walk along the lower border of the lake and find 
 solid rock all the way across the caflon. There is no doubt, 
 therefore, that the lake occupies a basin in solid rock. The 
 ledge confining the waters rises in places almost perpendicu- 
 larly to the height of over a hundred feet above the lake sur- 
 face, and indicates by its rounded contour and polished and 
 striated sides that the ice was once forced up from the basin, 
 now filled with water, and flowed over the ledges and down the 
 gorge. The sounding-line tells us that the bottom of the 
 basin is fifty-one feet below the lake surface. We thus have 
 a rock-basin of considerable depth, in the path of a glacier, 
 
 * " On the Glacial Origin of Certain Lakes," etc., " Quarterly Journal of the 
 Geological Society of London,' vol. xviil, 1862, pp. 185-204. 
 
270 
 
 THE ICE AGE IN XORTE AMERICA. 
 
 the unmistakable markings of wliicli descend into it on the 
 upper side and emerge again at its lower margin.* 
 
 'inhere is so much general interest in the question as to 
 the formation of the Yosemite Valley that we append the 
 remarks of the same high authority concerning it : 
 
 * "The Quaternary History of Mono Valley, California," pp. 281, 368, 369. 
 
GLACIAL EROSION AND TRANSPORTATION. 271 
 
 It is the opinion of the writer that the excavation of many 
 of the valleys of the Sierra Nevada began long previous to the 
 Quaternary, and are in fact relics of a drainage system which 
 antedates the existence of the Sierra as a prominent mountain- 
 range. 
 
 Those who seek to account for the formation of the Yo- 
 semite and other similar valleys on the western slope of the 
 Sierra by glacial erosion should be required to point out the 
 moraines deposited by the ice-streams that are supposed to 
 have done the work. The glaciers of this region were so 
 recent that all the coarse debris resulting from their action yet 
 remains in the position in which it was left when the ice 
 melted. If the magnificent valleys referred to are the result 
 of glacial erosion, it is evident that moi-aines of great magni- 
 tude should be found about their lower extremities. Observa- 
 tion has shown that debris piles of the magnitude and charac- 
 ter required by this hypothesis are notably absent. 
 
 It is perhaps not disgressing too far to state that the 
 writer, while visiting the Yosemite, could not avoid adopting 
 an hypothesis advanced some years since by J. D. Whitney, to 
 the effect that the main characteristics of the valley are due to 
 dislocation ; or, in other words, that the orographic block be- 
 neath the valley has subsided. No facts were observed, how- 
 ever, conflicting with the conclusion of - Clarence King that 
 the valley was occupied at least in part by glacial ice. The 
 majestic domes of the Yosemite region have not been rounded 
 by glacial action as some writers have supposed, but have been 
 produced by the weathering of granite, in which a concentric 
 structure on a grand scale was produced when the rocks were 
 in a plastic condition.* 
 
 Another illustration of the anomalous erosive power of 
 glacial ice is seen in the so-called cirques so abundant in gla- 
 ciated regions containing mountains. Here, again, we are 
 under great obligations to Mr. Eussell for his careful report 
 upon these features of the high Sierra. Little is to be added 
 to his discussion of the subject. 
 
 * " The Quaternary History of Mono Valley, California," pp. 360, 861. 
 
272 THE ICE AGE IN NORTH AMERICA. 
 
 One of the most striking features in the sculpturing of the 
 high Sierra is furnished by the grand amphitheatres or cirques, 
 occurring about the more elevated peaks and crests. These are 
 deep semicircular excavations, bounded on all sides, except that 
 through which the drainage escapes, by bold cliffs or by per- 
 pendicular walls from a few hundred to more than a thousand 
 
 Fir,. 83.— Glacial fnrvnws on Gibraltar Island, one half mile from preceding, but running; 
 nearly north and south. 
 
 feet in height. The bottoms of these excavations are often 
 depressed below that portion of the rim through which the 
 drainage escapes, and form rock-basins ; at other times the 
 basins are partially inclosed by debris, and in some instances 
 they have well-formed terminal moraines across their outlets. 
 In these hollows there are transparent lakes of azure blue, 
 which reflect the grandeur of the sheltering walls with wonder- 
 ful distinctness from their unruffled surfaces. A horizontal 
 cross-section of a cirque is semicircular or horseshoe-shaped, 
 and in certain portions of the range these are so numerous that 
 they give a scalloped contour to the faces of the cliffs. The 
 
GLACIAL EROSION AND TRANSPORTATION. 273 
 
 interiors of some of the amphitheatres are terraced in the same 
 manner as are the bottoms of the cafions leading from them, a 
 feature which has been observed in the cirques of the Eocky 
 Mountains as well. Nearly all the various branches of the 
 ancient glaciers of the high Sierra headed in deep recesses of 
 the character above described. In places the cirques occur on 
 eitlier side of a fragment of table-land, and have been eroded 
 back until only a knife-edge of rock, so narrow and broken 
 that the boldest mountain-climber would hesitate to traverse 
 it, is all that divides one profound depression from another. 
 Examples of this nature are common about Mounts Lyell 
 and Ritter, and find a number of typical illustrations in the 
 cliffs of the Kuna and Koip crests. At the head of Eush 
 Creek are a number of separate cirques, each holding a gem- 
 like lakelet, in wbich the various branches of the stream drain- 
 ing the basin have their source. Silver Creek heads in a 
 magnificent amphitheatre formed by the union of several 
 cirques, which during the height of the Glacial epoch was 
 completely filled with neve. On the south side of Kuna and 
 Koip peaks are two vast amphitheatres which rank among the 
 finest in the Mono region. ... No topographic delineation or 
 word description can convey the impressive grandeur of some 
 of these vast, shrine-like recesses that have been sculptured 
 during the lapse of centuries from the rugged cliffs of the high 
 Sierra. 
 
 In general the cirques open northward, but many excep- 
 tions to this rule can be found, especially about the head-waters 
 of Eush and Silver Creeks. 
 
 It is in the cirques about the higher peaks that living 
 glaciers are still found, and those not harboring perennial ice 
 are deeply filled with snow during a large portion of the year. 
 The slow melting of the snow and ice in these reservoirs feeds 
 the rills which join one with another to form the creeks flow- 
 ing into Lake Mono. The balance between the climatic con- 
 ditions favorable to the existence of glaciers and those which 
 insure their disappearance is here nicely adjusted, and, should 
 the equilibrium shift to the side of greater congelation, these 
 ancient cirques would be the first points to exhibit the changed 
 conditions. They were the fountains which gave birth to the 
 
274 THE ICE AOE IN RORTH AMERICA. 
 
 ancient glaciers, and were also the last strongholds to be aban* 
 doned when the reign of ice approached an end. 
 
 Such amphitheatres are known in all mountain-regions 
 where glaciers have existed. It has been the good fortune of 
 the writer to examine them on some of the higher peaks of 
 Colorado and New Mexico, about the crests of the Wahsatch 
 and East Humboldt Mountains, as well as in Switzerland and 
 New Zealand. Their origin is somewhat problematic, and has 
 occasioned much discussion, as is well known to all who have 
 followed the growth of glacial literature. 
 
 In an article on the formation of cirques, by T. G. Bon- 
 ney,* an attempt was made to prove that these peculiar feat- 
 ures of mountain sculpture are the result of stream-erosion, and 
 owe few if any of their characteristics to ice-action. 
 
 The studies of B. Gastaldi,t on the effects of glacial ero- 
 sion in Alpine valleys, led him to reject Bonney's hypothesis, 
 and to conclude that they are a result of ice-erosion. 
 
 The most extended as well as the most instructive essay 
 concerning their formation that has come under the writer's 
 notice is from the pen of Amund HeUand, entitled " On the 
 Ice-Fiords of North Greenland, and on the Formation of 
 Fiords, Lakes, and Cirques in Norway and Greenland. " J In 
 this essay a clear and concise desci'iption of the cirques of 
 Norway, Switzerland, and other regions is given, together 
 with a brief summary of the various hypotheses that have 
 been advanced in explanation of their origin. Strong evi- 
 dence is also presented to show that they are a result of glacial 
 action. In Helland's essay are included the views of Lorange, 
 of the Norwegian Koyal Engineers, who arrived at the con- 
 clusion that they are formed principally by the effects of 
 great changes of temperature in the vicinity of glaciers. We 
 quote Lorange's observations and conclusions as stated by Hel- 
 land : 
 
 "Under the glaciers in cirques, where a space intervened 
 between the bed of the cirque and the ice, he saw a great manv 
 
 * "Quarterly Journal of the Geological Society," London, vol. xxviii, 1872, 
 pp. 312-324. 
 
 f Ibid., vol. xxix, 1872, pp. 396-401. 
 X Ibid., vol. xxxiii, 1873, pp. 142-176. 
 
GLACIAL EROSION- AND TEANSPORTAriON. 275 
 
 stones, some of wiiich, sticking fast in the glacier, were quite 
 lifted up from the bed of the cirque, while others were touch- 
 ing or resting on it ; he thinks it probable that, as the tera- 
 lierature around the olacier constantly varies about the freez- 
 
 Fia. 81. — Glacial groove on Middle Bass Island. rmniinL 
 north-aiid-south j^'oove crossing it. Notice tlie bev( 
 .L^roove. which is nere descending to the west. 
 
 nearly east and west, with a 
 ed edge of the east-and-west 
 
 iug-]ioint, the incessant freezing and thawing of the water in 
 the cracks in the rock may split it, and the glacier may do the 
 work of transportation for the fragments thus broken loose. 
 On examining the interior of an empty cirque, we observe 
 that a bursting, not a scooping out. of the rocks has taken 
 place." 
 
 The writings of Penck, Lowl, and other European geolo- 
 
276 THE ICE AGE IN NORTH AMERICA. 
 
 gists might be cited here, hut it is not my intention to review 
 the entire literature of the subject. 
 
 SufiBclent observations have been recorded to show not 
 only that cirques are of nearly world-wide distribution, but 
 that they are confined to glaciated regions, and are not found 
 in mountains where undisputed records of glacial action are 
 absent. This in itself is good evidence that they have resulted 
 from glacial erosion. The same conclusion is indicated by the 
 fact that as a rule they open northward — that is, they occupy 
 positions where glaciers first appear when a lowering of tem- 
 perature renders their existence possible, and where they lin- 
 ger longest when the climate ameliorates. It thus seems un- 
 necessary to discuss in the present paper the various hypothe- 
 ses which refer their origin to water erosion, crater elevation, 
 etc. 
 
 The descriptions presented in the essays we have cited, 
 together with the observations of the writer, show that the 
 cirques of the high Sierra are typical of their class, and present 
 all the features to be seen in other similar regions. It is thus 
 rendered evident that, if we can arrive at an acceptable expla- 
 nation of their origin, it should explain the like phenomena 
 in other regions as well. The writer has no mature theory to 
 offer, but hopes to contribute something toward the desired 
 end. 
 
 It is usually difficult to di-aw a definite line between a 
 glacial cirque and the caflon leading from it. One is a contin- 
 uation of the other. It is evident, also, that the walls inclos- 
 ing a cirque have many features in common with the scarps so 
 frequent in glaciated caflons. When the cirques themselves 
 are terraced, this analogy is rendered still more complete. The 
 writer's studies in the high Sierra and elsewhere have led to 
 the conclusion that such scarps and ci'.'ques result mainly but 
 not wholly from glacial action. The initiation of the process, 
 at least in the high Sierra, as in the case of many glacial 
 cations, must have been by subaerial erosion. 
 
 Lorange's observations show that when a neve fills a 
 cirque it is capable of removing blocks of rock from the inclos- 
 ing walls. The fact that these walls are rough and angular, 
 instead of smoothly polished, is proof that there is but little 
 
GLACIAL EROSION AND TRANSPORTATION. 277 
 
 abrasion during the settling and consolidation of the neve in 
 the amphitheatres in which it accumulates. At the bottom of 
 the depressions, however, the conditions are different. Intense 
 glaciation there takes place, as is attested by the rounded 
 and striated surfaces, and by the occurrence of rock-basins. 
 The ice filling a cirque impinges with great weight upon its 
 bottom and in its motion outward tends to deepen the exca- 
 vation. At the same time the blocks loosened from the walls 
 of the cirque are carried away by the outward flow of the ice. 
 There are thus at least two processes which unite in enlarging 
 and deepening these peculiar features of glaciated mountain- 
 tops. 
 
 When a glacier leaves a cirque and flows down a canon 
 the grade of which is uneven, the erosion of the ice-stream will 
 also be uneven. The reason is that the ice in descending a 
 steep slope exerts its greatest force at the base of the incline in 
 the same manner as in the excavation of cirques. The tend- 
 ency .of a moving ice-stream in descending a steep slope is to 
 increase the inequalities of its bed ; this tendency, it seems 
 probable, will lead to the formation of both scarps and cirques 
 when the drainage of a high-grade valley is changed from a 
 liquid to a solid form. To illustrate : The grade of mountain 
 streams increases toward their sources, and when their gorges 
 become occupied by ice, the irregularities of their channels 
 — caused principally by the meandering of streams, thus leav- 
 ing projecting bosses on either side — may cause ice-cascades 
 in the glaciers. An ice-cascade exerts the greatest erosive 
 power at the base of the scarp which it descends, thus aug- 
 menting the inequality. At the same time the canon is broad- 
 ened and the minor features resulting from stream- erosion are 
 erased. The steeper the grade the more pronounced would be 
 the action of the ice in remodeling and strengthening the ma- 
 jor inequalities of its bed. The resulting scarps and terraces 
 should therefore be most numerous and best defined near the 
 heads of the channels in which they occur.* 
 
 The prevalence of cirques is also graphically described 
 by Dr. G. M. Dawson in his " Eeport upon the Forty-ninth 
 
 * " The Quaternary History of irouo Valley, California," pp. 362-355. 
 
278 THE IGE AGE IN NORTH AMEBIGA. 
 
 Parallel." Speaking of the streams which rise in the Rocky 
 Mountains, he says : 
 
 The upper ends of the valleys surrounding the higher peaks 
 and ridges are generally very abrupt and take the form of 
 cirques, or amphitheatrical depressions of great depth, in the 
 mountain - sides. The backs and sides of these are often 
 nearly vertical, and they are sometimes only separated later- 
 ally, by steep, knife-edge-like ridges, the crests of which form 
 the most practicable paths to the summits. Each of these 
 upper terminations of the valleys generally also shows a small 
 lake or pond in the hollow of the surrounding cliffs, the basin 
 of which has evidently been formed by glacier-ice — which must 
 here have been descending almost vertically — ^in the moraine 
 matter or shattered rocky floor. . . . The water of the smaller 
 lakes in the upper ends of the valleys, as seen from the heights 
 around, is of a beautiful semi-opalescent indigo-blue, and must 
 be of considerable depth.* 
 
 These facts confirm the theories of the leading glacialists 
 of Europe — for instance, Dr. Albrecht Penck, who ascribes 
 the excavations of the most important lake-basins in Bavaria, 
 like the Ammer See and Wurm See, to glaciers, and states 
 that " a lake-basin filled with water or sediment lies at the 
 mouth of each of the Alpine valleys through which glaciers 
 protruded in ancient times." f 
 
 The Scotch lochs, and the rock-basins of Norway, would 
 seem to be due to the same cause. It is probable also that 
 ^he fiords of Norway and of British Columbia owe their 
 greater depth near their heads to the same anomalous influ- 
 ence of ice-erosion. Most of the arguments nrged against 
 the theory are based upon d priori reasons urging the impos- 
 sibility of any such result from such a cause. Of this more 
 will be said when speaking a little later of the irregular depo- 
 sition of glacial debris underneath the moving ice. 
 
 Not enough is known about the nature of ice to affirm 
 
 * Page 245. 
 
 f Quoted by Newberry, in "School of Mines Quarterly," January, 1885, p. 10. 
 
GLACIAL EROSION AND TRANSPORTATION. 279 
 
 •that it does not conform to the law of ol-her moving fluids. 
 Probably there is no reason why an ice-cascade should not 
 produce results of erosion analogous to those of a waterfall. 
 
 Summarily stated, our conclusions are that, like every- 
 thing else connected with the action of such a complicated 
 cause as that brought into view in the production of glacial 
 phenomena, the exact extent of its erosive and transporting 
 power is difficult to determine. The action of ice over the 
 glaciated region took place after other forces had been in full 
 operation during long ages ; and hence it is often impossible to 
 separate the effects of the second cause from those of the first. 
 
 But there can be no doubt that running water is by far 
 the most efficient of all eroding agencies which have given 
 shape to the contour of the continents. Most important re- 
 sults follow from the power of water to act as a solvent. 
 Extensive regions have been undermined • and lowered 
 through the removal by water of the soluble salts. Such has 
 perhaps been the origin of many of the valleys of the Appa- 
 lachian region and of some of the great lakes of the world. 
 Running water is also a most effective mechanical agency, 
 continually acting along the natural lines of drainage. The 
 sand and gravel rolled along over the bottom of a rapid 
 stream of water act like a rasp or a saw, and have everywhere 
 worn deep narrow channels across the slowly rising mountain- 
 chains. Water as an eroding agency has had a great advan- 
 tage over ice in the far greater length of time during which 
 it has been in the field to operate. 
 
 Still, it can not be doubted that ice has had no small part 
 in transforming the appearance of the portions of the world 
 to which it has had access. Of this the evidence is abundant 
 in the great number and size of the bowlders scattered over 
 the glaciated region, hundreds of miles from their native 
 ledges, and weighing hundreds and even thousands of tons. 
 
 Inasmuch as ice is frozen water, its melting furnishes the 
 torrents to aid in the transportation. The finely comminuted 
 material ground up underneath the \om \p. largely carried away 
 
280 
 
 THE ICE AGE IN NORTH AMERICA. 
 
 by the torrential subglacial streams continually ponring out 
 from the ice-frout. It is doubtful if the larger part of the 
 glacial grist is not thus transported iar beyond the limit of 
 the glaciated region 
 
 Notwithstanding the great waste, the extent of the glacial 
 deposits yet remaining over the southern portion of the gla- 
 ciated region is immense. Probably not less than 1,000,000 
 squai-e miles of territory in North America is covered with 
 an average depth of fifty feet of glacial debris, forming the 
 most permanently productive portion of the continent. It 
 is in the extent of these glacial deposits, and in the certainly 
 great amount of transportation by subglacial streams, that we 
 have oiu' most certain and impressive evidence of the enor- 
 mous activity of erosive agencies during the Glacial age. 
 
 Fig. S,t— rowan bowlders south of Now Hampton, Iowa. (Photo by Calvin.) 
 
CHAPTEE XI. 
 
 DKUMLINS. 
 
 " Dbtjmlin " is the name now used to designate the class 
 of glacial accumulations which Professor Hitchcock origi 
 nally called " lenticular hills." These abound in the vicinity 
 of Boston, and large- 
 
 ly give character to 
 the scenery of the 
 three northeastern 
 counties of Massachu- 
 setts. They are not, 
 however, evenly dis- 
 tributed over the re- 
 gion. Familiar ex- 
 amples of them are 
 Beacon Hill, Boston ; 
 Bunker Hill, in 
 Charlestown; Breed's 
 Island Hill, beyond 
 East Boston; Green 
 Hill, in Winthrop ; 
 Powder - Horn Hill, 
 in Chelsea ; Mount 
 Kevere ; Mount 
 
 Washington, in Ever- 
 ett ; Tuft's College Hill ; Winter Hill and others, in Somer- 
 ville ; Bigelow Hill, in Brighton ; White's Hill, in Water- 
 town; Owl Hill, in Waltham; Mount Ida, Prospect, Insti- 
 tute, and Oak Flills, in Newton ; Corey's and Walnut Hills, 
 
 -Drumlme in the vicinity of Boston. (Davis.) 
 
282 THE lOE AGE IN NORTH AMERICA. 
 
 in Erookline ; Parker's Hill, in 
 
 Roxbury ; Bellevue and the 
 
 J. Clarendon Hills, in West Rox- 
 
 > bury; Brush Hill, in Milton; 
 
 Jones's Hill, Mount Ida, and 
 
 Pope's Hill, in Dorcliester ; 
 
 • WoUaston Heights, Forbes, 
 
 S President's and Great Hills, in 
 
 ■^ ^ Qnincy ; Great and King Oak 
 
 ' p HiUs, in Weymouth; Baker's, 
 
 * -^ J 6 Otis, Prospect, and Tui-key 
 
 a HiUs, in Hingham ; Scituate 
 
 1 and Bear Hills, in Cohasset ; 
 
 .- Strawberry and Telegraph Hills, 
 
 1 in Hull ; and the hiUs of Deer 
 
 < Island in the harbor. More 
 
 a than a hundred others of the 
 
 I same character occur within this 
 
 I area. 
 
 I Mr. Warren Upham's de- 
 
 I scription of these interesting 
 •o features of the landscape is 
 « most complete and satisfactory : 
 
 « These hills vary in size from 
 
 I a few hundred feet to a mile in 
 " length, with usually half to two 
 ^ thirds as great width. Their 
 £ height, corresponding to their 
 area, varies from twenty-five to 
 two hundred feet. But, what- 
 ever may be their size and height, 
 they are singularly alike in out- 
 line and form, usually having 
 steep sides, with gently sloping, 
 rounded tops, and presenting a 
 very smooth and regular contour. 
 From this resemblance in shape 
 
 / 
 
 « 
 
 1 b 4 
 
 1 
 
 i 
 
 f 
 
 r 
 
 k 
 
 ■4 
 
 •>t 
 
DRUMLINS. 
 
 283 
 
 to an elliptical convex lens. Professor 
 Hitchcock has called them lenticular 
 hills, to distinguish these deposits of 
 till from the broadly flattened or undu- 
 lating sheets which are common through- 
 out New Englaud. 
 
 The trend, or direction of the longer 
 axis, of these lenticular hills is nearly 
 the same for all of them comprised 
 within any limited area, and is approx- 
 imately like the course of the striae or 
 glacial furrows marked upon the neigh- 
 boring ledges. In eastern. Massachu- 
 sebts and New Hampshire, within twen- 
 ty-fiye miles of the coast, it is quite 
 uniformly to the southeast, or east- 
 southeast. Farther inland, in both of 
 these States, it is generally from north 
 to south, or a few degrees east of south ; 
 while in the valley of the Connecticut 
 Eiver it is frequently a little to the 
 west of south. In New Hampshire, 
 besides its accumulation in these hills, 
 the till is frequently amassed in slopes 
 of similar lenticular form. These have 
 their position almost invariably upon 
 either the south or north side of the 
 ledgy hills against which they rest, 
 showing a considerable deflection toward 
 the southeast and northwest in the east 
 part of the State. It can not be doubted 
 that the trend of the lenticular hills, 
 and the direction taken by these slopes, 
 have been determined by the glacial 
 current, which produced the striae with 
 which they are parallel.* 
 
 * " Proceedings of the Boston Society of Nat- 
 ural History," toI. xx, pp. 224, 226. 
 
 H4 
 
 I a 
 
 
 
284 
 
 TEE ICE AGE IN NORTH AMERICA. 
 
 To this may be added the following interesting remarks 
 by Professor William M. Davis : 
 
 The general uniformity of outline in any single region is 
 very noticeable ; indeed, the view from the summit of a com- 
 manding drumlin, in the center of a group, shows as character- 
 istic a landscape as that seen in looking from the Puy-de-D6me 
 over the extinct volcanoes of Auvergne. Moreover, the con- 
 trol that drumlins exercise over the laying out of roads and 
 the division of property is so complete in districts where they 
 abound, that it is the rule to find roads, fields, gardens, and 
 even houses oriented in obedience to the march of the old ice- 
 invasion. About Bos- 
 ton there are hundreds 
 of dwellings whose 
 walls thus stand in 
 close parallelism with 
 the glacial scratches 
 on bed-rock beneath 
 them. * 
 
 Besides the groups 
 of drumlins so prom- 
 inent in the vicinity 
 of Boston, there are 
 two or three others 
 deserving of mention, 
 and which may per- 
 haps be brought in. 
 to connection with 
 them.f One of these, 
 about eight miles wide 
 and twenty long, and 
 containing thirty or forty well-marked individual hills of the 
 character described, follows the coast from Beverly to N"ew- 
 bnryport. Parallel to this there is a belt of country, about 
 
 Fio. 89.— Dmmlins in northeastern Massachusetts. 
 (Davis.) 
 
 * "American Journal of Science," vol. cxxviii, 1884, p. 409. 
 t See map, p. 338. 
 
BRUMLmS. 
 
 285 
 
 four miles wide, over which scarcely any of these hills are 
 found. Still farther inland, a longer range can easily be 
 traced. Beginning in the vicinity of Portsmouth, JS . H., this 
 interior series is well developed, in a southwest direction, 
 through Rockingham county to Amesbury, Mass. Thence, 
 on, it completely covers the townships in Essex county on 
 either side of the Merrimack Eiver to Lowell, and continues, 
 wdth little interruption, through Middlesex county to the 
 zicinity of Fitchburg, Worcester county. To a limited ex- 
 tent these same typical hills abound still farther west through 
 the northern part of Worcester and Franklin counties to the 
 Connecticut River. Areas of them are also reported running 
 up from Ashbumham, Mass., to Weare, N. H. ; also in the 
 western part of Cheshire county, N. H., and in the vicinity 
 of Worcester, Mass., as well as about Amherst and in the 
 northeastern part of the State of Connecticut.* 
 
 The following additional facts have been collected by 
 Professor Davis : f 
 
 A fine series of drumlins stretches from about Spencer, 
 Mass., to Pomfret, Conn., but the detailed study that it would 
 well repay has not 
 
 yet been attempted. 
 Members of this 
 series occur near 
 Charlton station, 
 Boston and Albany 
 Kailroad, with their 
 bases at an elevation 
 of nine hundred feet 
 above sea-level, and 
 others stand still 
 higher. The por- 
 tion of the group in Connecticut is described by Percival as fol- 
 lows : " The district extending north from Hampton, through 
 
 FiQ. 90.— Outline of parallel drift-hills, in central New 
 York. (Davis.) 
 
 * Uphara, in " Proceedings of the Boston Society of Natural History," vol, 
 
 XX, pp. 231, 232. 
 
 \ "American Journal of Science," vol. cxxviii, pp. 410, 411. 
 
286 THE IGE AGE IN NORTH AMEBIC A. 
 
 Abington, Pomfret, and Woodstock, is characterized by a series 
 of very smoothly rounded, detached hills, in which the rock is 
 usually entirely concealed. These form a striking contrast with 
 the longer and more continuous [rocky] ridges of the adjoining 
 formation." * Professor G. H. Stone reports that drumlins of 
 large size, like those about Boston, have not been found in 
 Maine. Western New York, between Syracuse and Rochester, 
 presents a surprising number of parallel north-and-south drift- 
 hills, probably familiar to many travelers by rail. Some of them 
 are so long, smooth, and even, that the country thereabout 
 has been described as fluted. These were long ago described 
 by Professor James Hall, in his "Geology of the Fourth Dis- 
 trict of New York " (1843) ; since then they have been strangely 
 neglected until examined by Dr. L. Johnson, who has lately 
 published a paper, f entitled "The Parallel Drift Hills of 
 Western New York." Some of the ridges are "two or three 
 miles long, and attain elevations of one or two hundred feet 
 above the intervening valleys ; but the greater number are 
 shorter and steeper. Many of them were, when first cleared 
 of timber, very steep at their north ends, and on their east 
 and west sides ; but, with very rare exceptions, the southern 
 slope is gradual." These and other irregularities of form 
 
 f* * 
 
 ».=' I 
 
 Pre. 91.— Drumlins in Wisconsin. (Chamberiin.) 
 
 may require that some of the hills of this region should be 
 separated from drumlins as here defined. In Wisconsin, the 
 drift-hills, as described by President T. C. Chamberlin, "are 
 arranged in lines, and their longer axes invariably lie parallel 
 to the movement of the ice. In some localities, especially 
 
 * "Geology of Connecticut," 1842, pp. 256, 461, 479, 485. 
 
 t " Transactions of the New York Academy of Sciences," vol. i, 1882, p. W. 
 
BRUMLim. 287 
 
 in Dodge and Jefferson counties, these are mainly replaced by 
 long parallel ridges, sometimes several miles in length, with 
 corresponding linear marshes interspersed. Tliose correspond 
 accurately to the direction of the ice-motion." * According to 
 Mr. Upham, drumlins are not found in the abundant drift of 
 Minnesota. A few examples are mentioned for Pennsylvania, 
 near its western border, by Professor Lewis, f 
 
 In endeavoring to account for this class of hills, two or 
 three facts are of special importance : 1. The material of 
 which they are composed is very heavy and compact — almost 
 as heavy and compact, indeed, as ice. Such masses could 
 not have been shoved along bodily beneath the ice. In fact, 
 
 ^^B! 
 
 
 
 
 ^3 
 
 
 rWt 
 
 IF"" "• 
 
 Fis. 92.— Dnimliiis in (Joflstowi). N, H. (Hitrhr.jck. I 
 
 there would seem to be no reason why they might not resist 
 the erosion of the glacier almost as well as many of the softer 
 rocks did, especially when we remember that the pressure of 
 the ice on the bottom need not have been uniform, but 
 greater in some places than in others. 2. There are many 
 indications that these hills were formed by accretion undei- 
 the ice, there being, as Mr. Upham has shown, a tendency to 
 lamination or coarse glacial stratification in the structure of 
 
 * "Geoloi;yo£ Wisconsin," vol. i, 1883, p 283. 
 
 •)■ "Seconrl neological Survey of Pennsylvania, Z," pp. 29, IS 
 
288 THE ICE AGE IN NORTH AMERICA. 
 
 the hills.* 3. They are not characterized by kettle-holes. 
 The surfaces are remarkably symmetrical, as if having been 
 smoothed over by design, and all the irregular depressions 
 are filled with homogeneous earth. 4. Up to one hundred 
 feet above their base, the flanks of these hills in Massachusetts 
 and New Hampshire are frequently covered with the water- 
 worn deposits hereafter to be described and known as kames, 
 and which are the very last work done by the ice at the 
 points where they are found. The drumlins are, therefore, 
 earlier than the kames. 
 
 In structure these hills resemble the lower portions of till, 
 or the ground moraine. They are only imperfectly stratified, 
 and very compact, and filled with foreign and finely striated 
 stones. They are, without doubt, a true glacial deposit ; but 
 how comes the deposit to be heaped up in these localities in 
 such vast and shapely masses? Professor Shaler surmised 
 that they were but the remnants of a continuous ground 
 moraine which had been eroded from the whole country, 
 except where it was protected by pedestals or underlying 
 rock which served to break the force of the beating waves of 
 the ocean.f To this ingenious theory there are two fatal 
 objections: 1. Drumlins are frequently found where there 
 are no rocky pedestals to protect their bases. 2. They occur 
 in the interior far above any height to which it is supposed 
 the ocean has reached since the Glacial period. " The alti- 
 tudes at which they occur vary from the level of the sea to 
 fifteen hundred feet above it on the height of land between 
 the Merrimack and Connecticut Rivers." :{: Mr. Clarence 
 King would explain them as marking places in the great 
 continental glacier where streams of water which had run 
 for some distance in superficial channels along the surface of 
 the glacier and collected a great amount of debris from the 
 medial moraines, had finally plunged through a mmilin into 
 
 * " Proceedings of the Boston Society of Natural History," vol. xi, p. 22S. 
 f Ibid., vol. xiii, pp. 196-288. 
 X Ibid., ToL zx, p. 238. 
 
DRUMLINS. 289 
 
 a deeply hidden subglaeial river.* Here, it is thought, vast 
 cavities might be formed in which these accumulations would 
 take place, while, by the movement of the ice, the crevasse 
 might be transferred farther down, and so the accumulated 
 deposit be subjected to the pressure and sculpturing power 
 of the ice. 
 
 Mr. Upham speaks on the subject as follows : " The finely 
 pulverized detritus and glaciated stones in the bottom of the 
 ice-sheet had a tendency to lodge on the surface of any de- 
 posit of the same material. When such banks of the lower 
 till became prominent obstacles to the ice-current, its level- 
 ing force was less powerful than this tendency of adhesion, 
 which continually gathei'ed new material, building up these 
 massive rounded hills." f Mr. Upham remarks upon the par- 
 tial parallelism of these ranges of hills with the extreme ter- 
 minal moraine, and, with his usual perspicacity, notes that 
 both the glacial strise and the trend of the axes of the len- 
 ticular hills nearest the coast in Essex and SufEolk counties, 
 bear much more easterly than they do even a few miles in 
 the interior. This points with much force to the efEect which 
 would be produced upon the movement of the ice near its 
 margin when it had receded a considerable distance from the 
 south, but especially from the east, where the waters of the 
 Atlantic had access to the glacier along the margin of what 
 is called the Gulf of Maine. When the waters of this gulf 
 had eaten the ice well away into the Massachusetts shore, and 
 thus removed the barrier to.the east, the line of least resist- 
 ance would be in that direction, and the current would natu- 
 rally swing out toward the open sea. 
 
 While recognizing the force of all Mr. Upham says, I can 
 not forbear repeating an additional suggestion of my own 
 
 * I do not know as Mr. King has anywhere published these views, nor, in- 
 deed, as he would now be willing to own them, as here stated. They were 
 given me in personal conversation, and contain so much that is worthy of con- 
 sideration, that I venture to repeat the theory. 
 
 t " Proceedings of the Boston Society of Natural History," vol. xx, p. 
 234. 
 
290 TEE IGE AGE IN NORTH AMERICA. 
 
 made at the same time,* namely, that these hills perhaps 
 represent an earlier moraine than that on the south shore of 
 iS' ew England — i. e., one which was formed when, on the first 
 advance of the ice, it had reached the latitude of Boston, and 
 where for some reason it paused until great accumidations 
 had taken place along its front ; that afterward, upon a fresh 
 advance, these accumulations were overrun by the ice with- 
 out being leveled ; being merely sculptured by it, and read- 
 justed to the changing line of general movement ; and that, 
 finally, the retreat of the ice was so rapid over this region 
 that there were no marked terminal accumulations ; but the 
 superglacial debris settled gently over the whole country, 
 constituting the more highly colored superficial blanket of 
 debris called by Hitchcock " upper till," and furnishing the 
 larger and more angular bowlders characteristic of the super- 
 ficial deposits. I find also that Professor Charles Hitchcock 
 had made the same suggestion as early as 1876.f 
 
 The long discussion concerning the origin of these singu- 
 lar hills would seem to have been brought to a close by the 
 careful summary and discussion of facts given by Professor 
 Davis, from which we have already quoted : 
 
 The first clear reference to drumlins, as directly dependent 
 on glacial action for their form, was made by M. H. Close. J 
 They are here said to be parallel to the neighboring striae, and 
 hence, like these, dependent on the ice-sheet for their present 
 attitude and form. The same conclusion is presented in a 
 paper of 1866, when the name drumlin was first specially pro- 
 posed for them. Still later, when describing the physical 
 geography of the neighborhood of Dublin, Close writes, "It 
 is perfectly certain that it must have been the rock-scoring 
 agent which produced the bowlder-clay ridges." Besides this, 
 Kinnahan and Close, in a pamphlet of 1873, stated their opin- 
 
 * "Proceedings of the Boston Society of Natural History," vol. xx, p. 218; 
 also, "Prehistoric Andover,'' p. 4. 
 
 f Ibid., vol. xix, p. 66. Professor N. S. Shaler now favors this view ; see the 
 "Seventh Annual Report of the United States Geological Survey," 1888, p. 821. 
 
 X "Journal of the Royal Geological Society of Ireland," vol. i, 1864, p. 3. 
 
DBUMLINS. 
 
 291 
 
 ion that drumlins were formed in a way "similar to that by 
 which a stream of water often makes longitudinal ridges of 
 sand in its bed."* This is to 
 my mind the best suggestion yet 
 given to account for them. 
 
 J. Geikie wrote as follows : 
 "The remarkable linear direc- 
 tion of certain mounds of bowl- 
 der-clay in some districts of the 
 Lowlands, agreeing as this does 
 with the general bearing of gla- 
 cial markings of the same lo- 
 calities, induces us to believe 
 that we have here, with certain 
 modifications, the original con- 
 tour of the till after the super- 
 incumbent ice-sheet had disap- 
 peared " ; f but he believed that 
 these forms may be also in part 
 dependent on marine erosion. 
 In the "Great Ice Age," the 
 same author briefly mentioned 
 "the series of long, smoothly 
 rounded banks or drums, and 
 sow-backs, which run parallel 
 to the direction taken by the 
 ice," and regarded them as very Pio- 
 little modified from their glacial 
 form. They are "produced by the varying direction and un- 
 equal pressure of the ice-sheet," and are "the glacial counter- 
 parts of those broad banks of silt and sand that form here and 
 there upon the beds of rivers." Dr. L. Johnson says that he 
 accepts Geikie's explanation, and applies it to the New York 
 ridges which were "formed underneath the glaciers by alterna- 
 tions of lateral pressure " ; but this form of statement does not 
 commend itself so highly as the preceding. 
 
 Dramlins in Ireland, after Kin- 
 
 nahan and Close. (Davis.) 
 
 * " General Glaciation of lar-Connaught," Dublin, 1872. 
 
 ■f "Transactions of the Geological Society of Glasgow," vol. iii, 1867, p. 61. 
 
292 THE ICE AGE IN NORTH AMERICA. 
 
 In this country, Professor C. H. Hitchcock and Mr. War- 
 ren TJpham, while engaged on the geological survey of New 
 Hampshire, were the first to discover the parallelism between 
 glacial motion and the axes of drumlins in 1875. They con- 
 cluded that " the accumulation of these hills and slopes seems 
 to have been by slow and long-continued addition of material 
 to their surface, the mass remaining nearly stationary from the 
 beginning of its deposition. Obviously this was the case with 
 the lenticular slopes gathered behind the shelter of higher 
 ledgy hills or upon their opposite sides." * A little later TJp- 
 ham wrote, " Although we do not discover the cause of the 
 peculiar distribution of these hills, it seems quite certain that 
 they were accumulated and molded in their lenticular form 
 beneath the ice."t President- Chamberlin's observations led 
 him to a similar conclusion : " The drift presents some pecul- 
 iar tendencies to aggregation. ... A special tendency is ob- 
 served over certain considerable areas lying not far from the 
 Kettle Moraine to accumulate in mammillary or elliptical or 
 elongated hills of smooth-flowing outline." % And again, after 
 repeating this opinion, it is suggested that " a deeply hidden 
 boss of rock is usually and perhaps universally the determin- 
 ing cause of these peculiar accumulations." * 
 
 In reviewing these explanations and the observations on 
 which they are based, together with such evidence as my own 
 studies have discovered, the conclusion that drumlins should 
 be compared to sand-banks in rivers appears the most satisfac- 
 tory yet advanced. They seem to be masses of unstratified 
 drift slowly and locally accumulated under the irregularly 
 moving ice-sheet where more material was brought than could 
 be carried away. The evidence for the subglacial growth of 
 drumlins may be summarized as follows : The scratched stones 
 in the mass of bowlder-clay show a differential motion of its 
 several parts as they were scraped and rubbed along from a 
 generally northern source and gradually accumulated where 
 
 * " Geology of New Hampshire," vol. iii, p. 308. 
 
 ■f "Proceedings of the Boston Society of Natural History," vol. xx, p. 22S. 
 X " (leology of Wisconsin," vol. i, 1883, p. 283. 
 
 * " Third Annual Report of the United States Geological SuiTey," 1883. p. 
 SOR. 
 
BBUMLINS. 293 
 
 now found. The compactness of the mass suggests an origin 
 under heavy pressure ; the attitude of the hills demonstrates 
 a close dependence on the motion of the ice-sheet ; the super- 
 position of kanies on their flanks proves that their present 
 form was essentially completed when they were uncovered by 
 the ice-sheet, and the small change of form in the kames shows 
 that the drumlins also can have suffered very little from post- 
 glacial erosion ; the faint channeling of their smooth slopes by 
 rain measures the small amount of denudation that' they have 
 suffered since they were made. It must therefore be concluded 
 that they were finished closely as we now see them when the 
 ice melted away, and hence they were of subglacial construc- 
 tion. 
 
 The supposed manner of accumulation of drumlins may be 
 briefly sketched. It is well known that a stream of running 
 water will at one point carry along silt and sand that must be 
 dropped a little farther on where the current slackens, and the 
 bank thus begun grows slowly in a form of least resistance, at- 
 taining a maximum size when its increase of volume has so far 
 diminished the cross-section of the stream and consequently 
 increased the velocity that no more detritus can be dropped 
 there ; but even then one end may be worn away while the 
 other grows, the adjustment of velocity to channel is not per- 
 manent. The motion of a glacial sheet has been justly com- 
 pared to that of a broad river. The comparison may be ex- 
 tended so as to liken the active head-waters of a stream to the 
 presumably fast-moving part of the ice-sheet near its source or 
 center of dispersion where the greatest erosion generally takes 
 place. The delta of a river corresponds to the thinner and 
 slower - moving marginal area of an ice-sheet, where drift 
 brought from elsewhere is quietly and evenly deposited, as in 
 Minnesota, and where erosion is relatively weak. A still fur- 
 tier agreement is discovered in comparing the drumlins and 
 sand-banks found in the middle course of the molten a,nd solid 
 streams as suggested by the several authors quoted above. In 
 view of the irregularity of the surface on which the ice-sheet 
 moved and of the greater weakness of some rocks than others, 
 we must suppose an irregular velocity in the motion of tbe ice 
 and an unequal distribution of the rubbish beneath it. If the 
 
294 THE IGE AGE IN NORTH AMERICA. 
 
 faster motion at one place cause an excess of erosion there, the 
 slower motion at another place may bring about an excess of 
 deposition. This difference of action is known to prerail be- 
 tween the central and marginal parts of glaciated areas, and 
 the local accumulation of drumlins in an intermediate region 
 gives a smaller example of these two parts played by the ice. 
 If the causes of the irregular motion of the ice lie in the gen- 
 eral form of the country, the location of faster and slower cur- 
 rents will be relatively permanent ; the districts of faster cur- 
 rents would be found where the greatest volume of ice is 
 allowed to pass, and some of the points of retardation may be 
 the seats of long-continued drumlin-growth. The drumlins 
 thus begun will depend less upon the immediately local form 
 of the ground than on the topography of a more considerable 
 district, and hence we need not suppose every drumlin to have 
 begun its growth upon a knob of rock, although the beginning 
 of many hills may have been thus determined. Once begun, 
 the drumlins will go on increasing in size as long as deposition 
 exceeds erosion, always maintaining an arched form of least 
 resistance until a maximum size is reached or until the ice 
 melts away ; and in their growth they will approach the form 
 to which rough, i-ocky hills would be reduced by the reverse 
 process of erosion if time enough were allowed. Under un- 
 ending glaciation the whole surface must be rubbed down 
 smooth.* 
 
 As tbese theories relating to the formation of drumlins 
 involve the general principles upon which we are to explain 
 other evidences of the varying degrees of erosion effected by 
 moving ice, we may as well introduce here, as anywhere, Mr. 
 Greikie's general reply to the objections urged from the sup- 
 posed nature of the case : f 
 
 Our ice-sheet flowed, we can not doubt, with a differential 
 motion : it must have moved faster in some places than in 
 others. In steep valleys and over a hilly country its course 
 
 * "American Journal of Science," vol. cxxviii, pp. 413^16. 
 f " The Preservation of Deposits of Incoherent Materials under Till or 
 Bowlder Clay," in the " Geological Magazine," February, 1878, pp. 2, 3, 6, 7. 
 
DRUMLINS. 295 
 
 would often be comparatively rapid, but very irregular — 
 lagging here, flowing quickly there — while in wide, open 
 valleys that sloped gently to the sea, such, for example, as 
 those of the Forth and the Tweed, the whole body of the ice 
 would flow with a slower and more equable motion. As the 
 ice-sheet approached its termination, more especially if that 
 terminus chanced to be upon a broad and comparatively flat 
 region, like East Anglia, the erosive power of the ice would 
 become weaker and Veaker, for two reasons : first, because of 
 its gradual attenuation ; and, secondly, because of its con- 
 stantly diminishing motion. These, in a few words, are the 
 varying effects which one might a priori infer would be most 
 likely to accompany the action of a great ice-sheet. And an 
 examination of the glacial phenomena of this and other coun- 
 tries shows that the actual results are just as we might have 
 anticipated, had it been previously revealed to us that a large 
 part of our hemisphere was, at a comparatively recent date, 
 almost entirely smothered in ice. In places where, from the 
 nature of the ground, we should look for traces of great glacial 
 erosion, we find rock-basins ; in broken, hilly tracts, where the 
 ice-flow must have been comparatively rapid but irregular, and 
 the glaciation severe, we meet with roches moutonnees in abun- 
 dance, but with very little till ; in the open Lowlands and in the 
 broad valleys where the ice-sheet would advance with dimin- 
 ished but more equable motion, we come upon wide-spread and 
 often deep glacial deposits, and now and again with interglaeial 
 beds ; while over regions where the gradually decreasing ice- 
 sheet crawled slowly to its termination, we discover consider- 
 able accumulations of till, often resting upon apparently un- 
 disturbed beds of gravel, sand, and clay. 
 
 The distribution of interglaeial deposits, therefore, is really 
 in itself a proof that they have been overridden by ice. When 
 they occur in highly glaciated regions, it is only as mere 
 patches, which, occupying sheltered places, have been pre- 
 served from utter destruction. In the opener, low grounds 
 they are found in greater force, although in such places they 
 almost invariably afford more or less strong evidence of having 
 been subjected to much erosion and crumpling. But the far- 
 ther we recede from the principal centers of glaciation, and the 
 
296 TEB ICE AGE IN NORTH AMEBIC A. 
 
 nearer we approach the extreme limits reached by the ice- 
 sheets, the more extensive and the less disturbed do inter- 
 glacial deposits become. In a word, they occur in best preser- 
 vation where the erosive power of the ice was weakest ; they 
 are entirely wanting where we have every reason to believe that 
 the grinding force was strongest. ... 
 
 It is needless to refer one to the petty glaciers of the Alps 
 and Norway to prove that glacier-ice can not both erode its 
 bed and accumulate (?e5Ws upon that bed at one and the same 
 time. A mountain-valley glacier is one thing — a glacier ex- 
 tending far into the low grounds beyond the mountains, and, 
 it may be, coalescing with similar extensive ice-flows, is 
 another and very different thing. No considerable deposit 
 could possibly gather below Alpine glaciers like those of Switz- 
 erland and Norway ; but underneath glaciers of the kind that 
 invaded the low grounds of Piedmont and Lombardy we know 
 that thick deposits of tough bowlder-clay, crammed with 
 scratched stones, did accumulate ; and not only so, but that 
 these glaciers flowed over incoherent deposits of sand and clay 
 containing marine shells of late Tertiary age, without entirely 
 obliterating them. The deposits referred to occur now as little 
 patches within the area bounded by the great terminal mo- 
 raines. 
 
 As physicists themselves are not yet quite agreed upon the 
 subject of glacier motion, it is not incumbent upon the geolo- 
 gist to explain the precise mode in which a thick mass of ice 
 can creep over the surface of incoherent beds without entirely 
 demolishing them. It is enough for him to show how the 
 remarkable distribution of the interglacial beds, and the vari- 
 ous phenomena presented by these deposits, indicate that ice 
 has overflowed them. It is useless, therefore, to tell him that 
 the thing is impossible. The statement has been made more 
 than once that an ice-sheet several thousand feet thick is a 
 physical impossibility ; but, unfortunately for this dictum, the 
 geological facts have demonstrated that such massive ice- 
 sheets have really existed, and there appears to be one even 
 now covering up the Antarctic Continent. "We used also to be 
 told, not so many years ago, that the abysses of ocean must be 
 void of life for various reasons, among which one was that the 
 
DRUMLINS. 297 
 
 pressure of the water would be too great for any living thing 
 to endure. Yet many delicate organisms have been dredged 
 up from depths at which the pressure must certainly be no 
 trifle. Now, there seems to be just as little diflBculty in believ- 
 ing that these organisms existed in a perfect state at the bot- 
 tom of the ocean, as that shells imbedded in clay would remain 
 unbroken underneath the pressure of a superincumbent ice- 
 sheet of equal or greater weight. If the ice were in motion, 
 the clay with its included shells might be plowed out bodily, 
 or be merely crumpled and contorted ; or it might be ridden 
 over with little or no disturbance ; or, on the other hand, it 
 might become involved with subglacial debris, and be kneaded 
 up and rolled forward — the shells in this case being broken, 
 crushed, and striated, just as we find that the shells in certain 
 areas of till have been. The fate of the fossiliferous beds 
 would, in short, be determined by the rate of flow and degree 
 of pressure exerted by the superincumbent quasi-YisconB body 
 — the motion of which would be largely controlled by the 
 physical features of the ground across which it crept. 
 
CHAPTER XII. 
 
 PEEGLACIAL DRAINAGE. 
 
 Oke of the most marked effects of the Glacial period 
 was its influence upon drainage systems. The changes pro- 
 duced in numerous river-courses of North America by the 
 irregular deposits of till and modified drift, as well as by 
 the existence of temporary barriers of ice during the con- 
 tinuance of the continental ice-sheet, are subjects of unfailing 
 interest to the student of physical geography, and are also of 
 great practical significance in their relation to the economic 
 and hygienic interests of the country. 
 
 As compared with preglacial time, that which has elapsed 
 since the close of the Ice age is admitted by all to be very 
 short. Consequently, post-glacial erosion is much less than 
 preglacial erosion. Before the advent of the continental 
 ice-sheet, all the great valleys of North America had been 
 sculptured by preglacial streams,* The effects are still to 
 be seen even where extensive deposits of the Glacial period 
 have partially obliterated them. The sedimentary rocks, 
 occupying the basin of the Mississippi, and filling it with 
 strata thousands of feet in depth, serve as one index of the 
 extent of preglacial erosion ; for all the material of this class 
 of rocks has been ground up and transported by water. 
 Coming down from the neighborhood of the White Mount- 
 ains, the Adirondacks, and the Archaean highlands of Canada, 
 sediment-laden streams have, from the very earliest geologi- 
 cal ages, been engaged in wearing away the hills, scooping 
 
 * See Chapter X. 
 
PREQLAOIAL DRAINAGE. 299 
 
 out the valleys, and silting up the sea. The Alleghany 
 Mountains were at one time the bed of the ocean upon 
 which this sediment was deposited. The sandstones, shales, 
 and conglomerates of the coal-measures attest the activity 
 of the forces of that early period. The tops of the mount- 
 ains in southern New York and northern and eastern Penn- 
 sylvania are covered with subcarboniferous conglomerates of 
 almost incredible depth and extent, consisting largely of 
 well-rounded quartz pebbles, of all sizes up to two or three 
 inches in diameter. These are water-worn, and must have 
 been rolled along by impetuous currents from far-distant re- 
 gions. Thus the tributaries of the Mississippi are, at the 
 present time, bringing into its valley similar deposits from 
 the mountain plateaus on either side. But no sooner did 
 the convulsive forces of the earth begin to lift this great, 
 stratified ocean-bed of the Appalachian region above the 
 water, than it too became the subject of erosion, and began 
 to furnish material for newer deposits farther to the south 
 and west. 
 
 The Ohio Kiver and its tributaries furnish a good exam- 
 ple of the extent of preglacial erosion. The traveler is im- 
 pressed with the gorge in the Niagara Eiver below the falls, 
 as showing the force of running water when concentrated in 
 a single line of drainage. The gorge of the Niagara, how- 
 ever, is only about seven miles long, a thousand feet wide, 
 and three hundred feet deep. This, as will appear later,* 
 is one of the best measures of jjost-glacial erosion. But the 
 Ohio River, containing a far less volume of water, has worn 
 a much larger and deeper trough more than a thousand miles 
 in length. The character of the trough of the Ohio and its 
 tributaries is readily discerned, even by the passing observer. 
 The strata on the opposite sides are horizontal, and match 
 each other like the ends of a plank that has been sawed asun- 
 der. The alternate layers of conglomerate, coal, shale, and 
 sandstone upon the one side of the river correspond to simi- 
 
 * See Chapter XX. 
 
300 THE ICE A OE IN NORTH AMERICA. 
 
 lar layers on tte other side. The width of the gap cut by 
 the stream averages about a mile, with eclargements wher- 
 ever a tributary comes iu from either side. The tributaries, 
 also, occupy corresponding narrow valleys of erosion, extend- 
 ing even to their very sources in the mountains. The nature 
 of the cause producing these narrow troughs, and its long-, 
 continued operation in every one of these tributaries of the 
 Ohio, are not difficult to see. They have all been formed by 
 running water. The Tennessee, the Cumberland, the Ken- 
 tucky, the Wabash, the Miami, the Licking, the Scioto, the 
 Big Sandy, the Kanawha, the Hocking, tlie Muskingum, the 
 Big Beaver, the Monongahela, and the Allegliany, together 
 with their tributaries, all show the vast amount of water- 
 erosion along these lines of preglacial drainage. 
 
 But even these do not, in their present condition, reveal 
 the whole extent of the effect of the constant and long-con- 
 tinued erosive forces of preglacial times. The ancient bed 
 of the Ohio River was certainly one hundred and fifty feet 
 deeper than that over which it now flows, it having been 
 filled with glacial debris to its present level. According to 
 Professor Newberry — 
 
 At the junction of the Anderson with the Ohio, in Indiana, 
 a well was sunk ninety-four feet below the level of the Ohio 
 before rock was found. In the valley of Mill Creek, in the 
 suburbs of Cincinnati, gravel and sand were penetrated to the 
 depth of one hundred and twenty feet below the stream before 
 reaching rock. On the margin of the Ohio, at Cincinnati, 
 gravel and sand have been found to extend to a depth of over 
 one hundred feet below low-water mark, and the bottom of 
 the trough has not been reached. The falls of the Ohio, formed 
 bv a rocky baiTier across the stream, though at first sight 
 seeming to disprove the theory of a deep continuous channel, 
 re;il]y affords no argument against it ; for here, as in many 
 other instances, the present river does not follow accurately 
 the line of the old channel, but runs along one side of it. At 
 the Louisville falls, the Ohio flows over a rocky point which 
 proiects from the north side into the old valley, while the deep 
 
PREOLACIAL DRAINAGE. 301 
 
 channel passes on the south side, under the lowlands on which 
 the city of Louisville is built. 
 
 The tributaries of the Ohio exhibit the same phenomena. At 
 New Philadelphia, Tuscarawas county, the borings for salt-wells 
 show that the Tuscarawas is running one hundred and sev- 
 enty five feet above its ancient bed. The Beaver, at the junc- 
 tion of the Mahoning and Chenango, is flowing one hundred 
 and fifty feet above the bottom of its old trough, as is dem- 
 onstrated by a large number of oil-wells bored in the vicinity. 
 Oil Creek is shown by the same proofs to run from seventy- 
 five to one hundred feet above its old channel, and that chan- 
 nel had sometimes vertical and even overhanging walls.* 
 
 Additional particulars of much interest concerning buried 
 channels in the Ohio are given by other geologists. For ex- 
 annple, Professor Joseph F. James presents cogent reasons 
 for believing that the northward bend of the Ohio Eiver, now 
 culminating at Cincinnati, continued still farther north pre- 
 vious to the Glacial period, and extended througb Mill Creek 
 up to join the valley of the Great Miami at Hamilton. He 
 supposes that the main stream then ran north of the city 
 through the valley in which Madisonville is situated. The 
 evidence of this is, that below Cincinnati, a short distance, 
 the present river flows, beyond all doubt, over bedded rock 
 between Price Hill and Ludlow, Ky. ; while borings show 
 that up Mill Creek several miles the bed-rock lies certainly 
 thirty-four feet below low-water mark, while at Hamilton, 
 twenty-five miles north of Cincinnati, the preglacial valley 
 is found to be filled up to a depth of more than two hundred 
 feet, and the bed-rock lies ninety-one feet below low-water 
 mark in the Ohio at Cincinnati.f 
 
 Mr. M. C. Read, among other numerous references to 
 buried channels, describes one in Knox county, east of Gam- 
 bier, in the valley now occupied by Owl Creek, where the 
 
 * " Geological Survey of Ohio," vol. ii, pp. 13, 14. 
 
 f " Journal of the Cincinnati Society of Natural History," July to October, 
 1888, pp. 96-101, and a subsequent personal communication. 
 
302 THE IGE AGE IN SORTS AMERICA. 
 
 bed-rock lies eighty-two feet below tbe bottom of the present 
 stream. West of Mount Liberty, in the same county, the 
 drift conceak an old gorge two hundred and eighty-five feet 
 deep.* Mr. P. Max Foshay, in a paper before the American 
 Association for the Advancement of Science, in 1888, gives 
 many reasons for supposing that Beaver Creek, which now 
 empties into the Ohio, was connected by a buried channel 
 with Grand River, emptying into Lake Erie at Painesville, 
 and hence that a still larger portion of the upper Ohio drain- 
 age than was supposed by Mr. Carll passed into the St. Law- 
 rence Valley. This suggestion was first made by Professor 
 Spencer and indicated on one of his maps over twenty years 
 ago. 
 
 Every day is demonstrating that the present level appear- 
 ance of the surface of the northwestern portion of Ohio is 
 due to the extensive deposits of the Glacial period, whose 
 effect has not been so much to make the hills low as to exalt 
 the valleys. Professor Orton long ago called attention to the 
 numerous buried channels near Springfield in Clarke county, 
 one of which is occupied by the New Tork, Pennsylvania, 
 and Ohio Railroad.;]: The extensive explorations for stores 
 of gas and oil now in progress in the western part of Ohio 
 and the eastern part, of Indiana are bringing to light btuied 
 channels in most unexpected places, that at St. Paris, Cham- 
 paign county, being more than five hundred feet deep. This 
 is an extreme case, but it illustrates what a network of pre- 
 glacial gorges have been plastered up by the ice-movement 
 which passed over the region. The country resembles, on a 
 large scale, a checked and worm-eaten plank which a carpen- 
 ter has filled with putty. 
 
 One of the first effects of this filling up of the preglacial 
 channels has been so to change the lines of superficial drain- 
 age, in a great multitude of instances, that the streams are 
 now made to run over rocky beds at levels far higher than 
 
 * "Geological Survey of Ohio," vol. iii, pp. 325-347. 
 X "Geological Survey of Ohio," vol. i, pp. 450^0. 
 
PBEOLAOIAL DRAINAGE. 303 
 
 lihey had formerly occupied. Thus it is that the glaciated 
 region becaioe again a region of waterfalls. Almost every 
 stream entering Lake Erie from the south exhibits waterfalls 
 produced in this manner. In Minnesota the falls of St. 
 Anthony, at Minneapolis, and of Minnehaha, a few miles be- 
 low, were thus produced, and, so, are post-glacial in their 
 origin, the ancient channels having been filled with glacial 
 debris. 
 
 The falls of Niagara are due to the same cause. The pre- 
 glacial outlet to Lake Erie was dammed up and buried by 
 glacial debris, so that the water was compelled to seek 
 another channel. Before the lee age there was no Niagara 
 River, and Lake Erie is, in fact, but a glacial mill-pond. 
 The falls of the Genesee at Rochester are also clearly due to 
 the same cause. The preglacial valley in the Genesee is now 
 deeply buried. " Between Mount Morris and Rochester the 
 river follows its preglacial valley, but flows for much of this 
 distance on an alluvial plain that closely resembles the filling 
 of an old lake ; above and below the limits named the river 
 has cut a new channel since glacial times, giving some of the 
 best natural sections in the State, and its old course is choked 
 with drift." * 
 
 The falls of the Mohawk at Cohoes, also, doubtless indi- 
 cate the existence of a deeply buried channel somewhere in 
 the vicinity, connecting, as we shall see a little later, the 
 basin of Lake Ontario with the Hudson. 
 
 The evidence that the preglacial outlet of Lake Erie was 
 much lower than its present outlet, lies in the fact that sev- 
 eral rivers now entering the lake from the south flow at a 
 level two hundred feet above that formerly occupied by them, 
 since that distance has been penetrated beneath their present 
 bottom before reaching rock. From various borings at Cleve- 
 land it appears that rock bottom at the mouth of the Cuy- 
 ahoga lies more than 500 feet below the level of the lake, 
 and is at a depth of at least 200 feet twenty miles in land. 
 
 *See Professor W. M. Davis, in the "Proceedings of the Boston 
 Society of Natural History," vol. xxi, p. 359. 
 
304 THE ICE AGE IN NORTH AMERICA. 
 
 Thus, since the elevation of Lake Erie is only 373 feet above 
 tide, the rock bottom of the Cuyahoga River, though 700 miles 
 inland, is now nearly at sea level. Newberry also discovered 
 that Grand and Rocky rivers flow over deeply buried 
 channels. In the case of Rocky River, Dr. D. T. Gould has 
 
 £oitan I^cdgCf 
 
 Fig. 94.— Section acrosa the valley of the Cuyahoga River, twenty miles above its mouth 
 
 (Claypole.) 
 
 traced the buried channel southward for a distance of nearly 
 thirty miles, or into its upper waters in Medina county. This 
 he has done by collecting the record of wells along the route, 
 and by noting various places where the present stream crosses 
 the old bed, passing out of rocky banks for a short distance, 
 and running through clay banks and over a clay bottom to 
 enter its new channel again between rocky walls. 
 
 Professor Spencer has also shown, with great probability, 
 what was the preglacial line of drainage thtough which the 
 waters, both of Lake Huron and of Lake Erie, flowed to enter 
 Lake Ontario on their way to the sea. The line, as he first 
 thought, passes out of Lake Huron through the valley of the 
 Au Sable, crossing the Thomas River near London, in Canada, 
 and entering the basin of Lake Erie a little east of Port Stan- 
 ley. Thence, after passing around Long Point and Island, it 
 bends northward through the valley of Grand River, and 
 enters Lake Ontario at its extreme western point.* From 
 later information, furnished me by letter, it appears that Pro- 
 fessor Spencer is inclined now to make the connection be- 
 tween Lake Huron and Lake Ontario direct, passing through 
 Georgian Bay, and reaching Ontario in the vicinity of Toron- 
 
 * " Second Geological Survey of Pennsylvania," Q*, pp. 367-406. 
 
PREOLAGIAL DRAINAGE. 305 
 
 to, as shown in his accompanying map. Thence, according to 
 Newberry, the ancient line of drainage passed through On- 
 tario, and emerged in a stream occupying the valley of the 
 Mohawk, to swell the current of the Hudson rather than 
 that of the St. Lawrence.* 
 
 The facts concerning this line of preglacial drainage had 
 been thus succinctly stated by Professor Newberry in an ear- 
 lier paper : 
 
 Some of the streams draining into the basin of Lake Ontario 
 in former times cut their channels below the present ocean- 
 level. All the salt-wells of Syracuse are sunk in one of these, 
 which is filled with gravel and sand saturated with brine issu- 
 ing from the salina group that forms its walls. The rock-bot- 
 tom of this old river-bed was reached in some of these wells at 
 a depth of fifty feet below the present level of tide-water. 
 
 The valley of the Mohawk is a very deep channel of erosion, 
 now half filled, which must have been traversed by a large 
 stream flowing eastward at a level below that of the present 
 ocean ; and everything indicates that this was the ancient out- 
 let of the basin of the Great Lakes. 
 
 The channel of the Hudson is apparently the only possible 
 continuation of this long line of drainage. As has been re- 
 marked, it is of great and yet unknown depth. The clay by 
 which it is partially filled has been penetrated to a depth of 
 about one hundred feet along its margins. How deep it is in 
 the middle portion can only be conjectured ; but Hell-Gate 
 Channel, which has been kept comparatively free by the force 
 of the tides, is in places known to be nearly two hundred feet 
 deep ; and, since this is a channel of erosion formed by a stream 
 draining into the Hudson, the ancient bed of the Hudson must 
 be still lower, t 
 
 The silting up of these preglacial outlets has enlarged 
 Lakes Ontario and Huron far beyond their previous limits, 
 and wholly created Lake Erie. Lakes Michigan and Superior 
 
 * Paper read before the American Philosophical Society, November 4, 1881, 
 
 p. 93. 
 
 f "Popular Science Monthly," vol. xiii, p. 16. 
 
306 TBE ICE AGE IN NORTH AMERICA. 
 
 were likewise greatly enlarged by the damming up of outlets 
 ■which formerly conducted their waters southward into the 
 Mississippi. These barriers also turned the surplus waters 
 of those inland seas toward the east. The outlet of Lake 
 Superior through the rapids of the Sault Ste. Marie is caused 
 by the increased depths of the glacial deposits to the west 
 across the narrow isthmus separating it from Lake Michigan, 
 where, doubtless, a ship-canal could be cut between these two 
 lakes without encountering any rocks at all. From the south- 
 em end of Lake Michigan, also, a deeply-buried preglacial 
 channel is believed to ran southwest, through Kankakee, 
 Livingston, and MacLean counties, toward the Mississippi. 
 
 Professor Newberry's theory ot the eastward preglacial 
 drainage from the region of Lake Ontario meets with insuper- 
 able difficulties, notwithstanding the apparent support it 
 would receive from the startling facts recently brought to 
 light concerning the depth of the preglacial trough of the 
 Hudson River, where the engineers sounding for a foundation 
 for a conduit to convey water from the Catskill region to 
 New York City in 1906, found that a short distance above 
 West Point the rock bottom of Hudson River was 487 feet 
 below the present bottom. The depth of the buried channel 
 between New York and Newark is not certainly known, but 
 the numerous railroad tunnels under the river are uniformly 
 through unconsolidated sedimentary deposits, and in case 
 of the Pennsylvania road abutments are sunk to a consider- 
 able depth in the mud to support the timnel, as if it were a 
 bridge. Outside the harbor of the city this preglacial outlet 
 has been traced by the sounding line of the Coast Survey for a 
 distance of a hundred miles, to the edge of the deep water of 
 the Atlantic. Over a considerable portion of this distance it 
 has a width of more than a mile and is 2,000 feet deep. These 
 facts concerning the Hudson, brought to light since Professor 
 Newberry's death would have greatly strengthened his 
 argument. There is, however, one fatal objection to his con- 
 
PREGLACIAL DRAINAGE. 307 
 
 elusion. At Little Falls, a spur of archaean rocks projects 
 from the Adirondack Mountains and effectually separates 
 the preglacial drainage of the western part of the state from 
 that of the eastern. Professor Newberry had supposed that 
 there was room for a deep preglacial channel to lead around 
 this obstruction, but fuller examination shows that this 
 could not have been the case. The upper part of the St. 
 Lawrence is also crossed by continuous strata of archaean 
 rocks, showing that there was no preglacial channel permitting 
 drainage in that direction. 
 
 To a superficial observer it would seem that the way was 
 equally closed into the Mississippi Valley. For it would 
 appear in the highest degree unlikely that the drainage of 
 Lake Ontario, whose bottom is now 507 feet below tide 
 level, could ever have found a way across the intervening 
 highlands which separate it from the Mississippi Valley, the 
 lowest place of which (at Chicago) is more than 600 feet above 
 tide level. But our conception of the depth of the glacial 
 deposits over this . intervening area, and of the preglacial 
 gorges that have been filled by them has been enormously 
 enlarged by every fresh investigation of the region. 
 
 The course of preglacial drainage in the upper basin of 
 the Allegheny River is worthy of more particular mention. 
 Mr. Carll, of the Pennsylvania Geological Survey, has conclu- 
 sively shown that previous to the Glacial period the drainage 
 of the valley of the upper Allegheny north of the neighbor- 
 hood of Tidioute, in Warren county, instead of passing south- 
 ward, as now, was collected into one great stream flowing 
 northward through the region of Cassadaga Lake to enter the 
 Lake Erie basin at Dunkirk, N. Y. The proof of this is that 
 between Tidioute and Warren the present Allegheny is shal- 
 low, and flows over a rocky basin; but from Warren north- 
 ward, along the valley of the Conewango, the bottom of the 
 old trough lies at a considerably lower level, and slopes to 
 the north. Borings show that in thirteen miles the slope of 
 
308 THE ICE AGE IN NORTH AMERICA. 
 
 the preglacial floor of Conewango Creek to the north is 136 
 feet. The actual height above tide of the old valley floor at 
 Fentonville, where the Conewango crosses the New York line, 
 is only 964 feet; while that of the ancient rocky floor of the Al- 
 legheny at Great Bend, a few miles south of Warren, was 1 , 170 
 feet. Again, going nearer the head waters of the Allegheny, 
 in the neighborhood of Salamanca, it is found that the ancient 
 floor of the Allegheny is, at Carrollton, seventy feet lower than 
 the ancient bed of the present stream at Great Bend, about 
 sixty miles to the south; while at Cole's Spring, in the neigh- 
 borhood of Steamburg, Cattaraugus County, N. Y., there has 
 been an accumulation of 315 feet of drift in a preglacial valley 
 whose rocky floor is 155 feet below the ancient rocky floor at 
 Great Bend. There must, therefore, of necessity have been 
 some other outlet than the present for the waters collecting 
 in the drainage-basin to the north of Great Bend. 
 
 While there are numerous superficial indications of buried 
 channels running toward Lake Erie in this region, direct ex- 
 ploration has not been made absolutely to demonstrate the 
 theories. But, if resorted to, we know, from the facts just 
 stated, that the line of some such drainage valley must be dis- 
 covered. In the opinion of Mr. Carll, Chautauqua Lake did 
 not flow directly to the north, but, passing through a channel 
 nearly coincident with that now occupied by it, joined the 
 northerly flowing stream a few miles northeast from James- 
 town.* It is probable, hovpever, that Chautauqua did not 
 then exist as a lake, since the length of preglacial time would 
 have permitted its outlet to wear a continuous channel of 
 great depth corresponding to that known to have existed in 
 the Conewango and upper Allegheny. 
 
 Farther west as already sho-rni, the Middle Allegheny 
 appears to have followed a channel leading past Meadville 
 through French Creek to the Lake in the vicinity of Erie, 
 Pa., while the drainage of the Monongahela was clearly north- 
 ward through Beaver Creek and the Mahoning and Grand 
 
 * "Second Geological Survey of Pennsylvania," iii. 
 
PREGLACIAL DRAINAGE. 309 
 
 River valleys to Lake Erie, a little west of Ashtabula. This 
 was demonstrated by Mr. Hice, who discovered pot-holes 
 on the rock terraces of Beaver Creek all pointing northward. 
 This line of preglacial drainage of the Upper Ohio has been 
 chosen by the engineers as the best route for the canal to 
 connect Lake Erie with the Ohio Valley. The portion of the 
 Upper Ohio following this line in preglacial times is that above 
 Martinsville, where there is a well marked narrow place in 
 the gorge indicating a preglacial col between two systems of 
 drainage. The water, being thrown over this by the glacial 
 dam, speedily eroded a channel such that upon the melting 
 of the ice the water continued to flow in that direction. 
 
 According to the investigations of Professors Tight and 
 Bownocker, it would seem, also, that thedrainageof the Middle 
 Ohio was through buried channels leading to the northwest, 
 along a line nearly coinciding with the valley of the Scioto. 
 As will be detailed more fully in another chapter (p. 379, 
 seq.) the Middle Ohio, below Martinsville flowed southwest 
 as far as Huntington, West Virginia, where it was joined by 
 the Kanawha, a still larger stream coming down from the 
 Appalachian Mountains through the deserted channel of 
 Teazes Valley. At Huntington the united current turned 
 northward to the vicinity of Portsmouth at the mouth of the 
 present Scioto, where it was met by a shorter stream flowing 
 eastward from a col in the Ohio at Manchester. Ten miles 
 above Portsmouth, at Wheelersburgh the Little Scioto enters 
 the Ohio after having flowed for many miles through a broad 
 abandoned channel, which near the village of California 
 inosculates with another running northwestward into the 
 Scioto at Waverly. It is the opinion of Mr. Leverett, and of 
 Professors Tight and Bownocker, that the Kanawha drainage 
 in preglacial times took this course, and then proceeded in a 
 northward direction through the buried channel of the Upper 
 Scioto. 
 
 A little below Columbus this stream was joined by one 
 
310 
 
 THE ICE AGE IN NORTH AMERICA. 
 
 emerging from the Tuscarawas Valley through a clearly 
 marked buried chamiel leading from one valley to the other 
 at Newark. At the present time the Tuscarawas drainage 
 turns a right angle at Dresden and flowing south to Zanes- 
 ville is joined by the Licking River coming from the north- 
 west, and both flow southward through a narrow, and clearly 
 post-glacial valley to the Ohio at Marietta. 
 
 The whole country north of Columbus is so deeply covered 
 with glacial drift that it is impossible to trace the preglacial 
 drainage except through the aid of borings which have been 
 made in search of aitesian water, or of gas and oil. But these 
 have revealed so many deep canons, in some cases more than 
 
 FiQ. 95 — Cross-section from Sonora, IlUnols, to Ar^yle, Iowa, showing old and new chan* 
 nela of the Mississippi River. (From Iowa Geological Survey.) 
 
 500 feet in depth, that it is bj' no means impossible, or even 
 improbable that the whole drainage led off into the Wabash 
 Valley, or perhaps more directly north into the bed of Lake 
 Erie, and so around into the Wabash or Illinois. 
 
 The preglacial drainage of the Lower Ohio is equally inter- 
 esting. As already shown, and as appears graphically in the 
 map on p. 643, the Licking River of Kentucky continued 
 north from Cincinnati through the valley of Mill Creek, hav- 
 ing been joined at Ivorydale by that portion of the preglacial 
 Ohio which came from the col below the mouth of the Scioto. 
 This united stream, after reaching Hamilton, probably turned 
 southward through the channel of the Great Miami, which is 
 much broader than that of the Ohio just below Cincinnati. 
 Below Lawrenceville, Indiana, there has been little change in 
 
PREOLACIAL DRAINAGE. 311 
 
 the course of the river since preglacial times except in the 
 vicinity of Louisville, Kentucky, where it now flows over a 
 rocky barrier constituting the Falls which obstruct navigation 
 at this point. There is, however, a deeply buried channel 
 south of Louisville filled with the coarser silt bought down by 
 glacial floods from the melting ice which reached and crossed 
 the river for some distance above. 
 
 Coming to the Mississippi River two preglacial channels 
 are of special interest. One lies just west of Minneapolis, 
 following a wide shallow depression dotted with small lakes 
 and entering the valley of the Minnesota a short distance 
 above Fort Snelling, where the present Mississippi joins the 
 valley. This preglacial gorge is now filled with glaci.al debris 
 to a depth of 200 feet or more. The present Mississippi 
 after plunging over the Falls of St. Anthony occupies a narrow 
 rocky gorge, which it has worn since glacial times, to its 
 junction with the main valley. 
 
 A similar broad, deep preglacial valley channel of the 
 Mississippi now filled with glacial debris is found west of 
 Keokuk, Iowa. This became so completely filled with till 
 that the river was forced to seek its present channel, which 
 passes over rocky rapids at Keokuk, compelling the govern- 
 ment to construct there a canal with locks for the sake of 
 navigation. (See Fig. 95). 
 
 In Professor I. C. White's report upon Pike and Monroe 
 counties, Pennsylvania,! he gives an account of no less than 
 twenty-three channels which have been buried by glacial 
 debris. Among these that of the Wallenpaupack Creek is 
 the most striking. At present this creek empties into the 
 Lackawaxep at Paupack Falls, where it descends 260 feet in 
 a mile. But on ascending the creek two or three miles, to 
 the vicinity of Tafton, the course of a preglacial valley can 
 be easily recognized, leading into Kimball's Run, and join- 
 ing the Lackawaxen at Kimball's Station. This channel is 
 
 tibid, G«, pp. 52-63. 
 
312 THE ICE AGE IN NORTH AMERICA. 
 
 now buried to a depth of 300 feet for a distance of many 
 miles. 
 
 R. W. Ells calls attention, also, to the numerous buried 
 channels* in the Eastern Townships, in the province of Que- 
 bec, in the vicinity of Lake Memphremagog. These are, to 
 a considerable extent, explored at the present time for the 
 sake of the gold found in them. 
 
 These are but a few of the innumerable facts indicating 
 that before the great Ice Age not only the Ohio, but nearly 
 all the streams of the eastern United States, occupied deeper 
 channels than they now do. There were then probably no 
 Great Lakes, and few if any waterfalls, as there are now no 
 lakes and waterfalls south of the glaciated region. All the 
 rivers had cut their channels down so low that they drained 
 to the bottom any lakes that may have once existed. 
 
 * "Annual Report of the Geological and Natural History Survey of 
 Canada," vol. ii, 1866, p. 49, J. 
 
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CHAPTEE XIII. 
 
 DEAINAGE OF THE GLACIAL PEEIOD. 
 
 DuEiNG the continuance of the lee age, an extraordinary 
 factor was in the field to modify the lines of drainage, and 
 to give to them both a direction and a character such as they 
 never had had at any other time. Throughout the whole ex- 
 tent of the Glacial period the ice itself was a most important 
 barrier, deflecting the course of the streams, and, at the same 
 time, was a cause of irregularity in the volume of water 
 such as is altogether unique in the history of the world. The 
 vast mass of frozen water then stored up at a high level was 
 an immense reservoir of force, ready, on proper conditions, 
 to descend in torrents through any channel which was opened 
 before it. 
 
 As the ice of the Glacial period advanced southward from 
 the Laurentian highlands, it reversed the currents of all the 
 great rivers which flowed to the north. One of the first and 
 most remarkable effects of this advance must have been the 
 damming up of Nelson Kiver, so as to cause the surplus 
 water — ordinarily flowing through Hudson Bay into the 
 North Atlantic — to pour over into the head-waters of the 
 Mississippi and so into the Gulf of Mexico. Thus, from the 
 beginning of the Glacial period to its close, the Mississippi 
 River must have been the channel through which was carried 
 off the waste water from the larger part of the Dominion of 
 Canada as well as from the central portion of the United 
 States. A little later, also, the drainage of the Great Lake 
 region must have been obstructed toward the northeast and 
 east; for, long before the eastern lobe of the glacier had 
 
314 THE WE AGE IN NORTE AMERICA. 
 
 reached the latitude of !N"ew York city, the valleys of the St. 
 Lawrence and of the Mohawk must have been closed up by 
 ice so as to reverse their lines of drainage. The waters of 
 Lakes Superior and Michigan must then have flowed into the 
 Mississippi River along the lines of the Fox, Wisconsin, and 
 Illinois Rivers, while those of Lakes Huron and Erie poured 
 into the Ohio River, at flrst down the Wabash, then, a little 
 later, when the extension of the central lobe of ice cut off the 
 western outlet of Lake Erie, over the lowest places in the 
 water-shed into the valleys of the Scioto, the Muskingum, 
 and Beaver Rivers ; at the same time, every northern tribu- 
 tary of the Alleghany was a glacial flood. 
 
 But the scenes to have been witnessed during the ad- 
 vance of the ice-sheet are as nothing compared with those 
 which must have occurred during its retreat. Even now, 
 every spring has its freshets, when the combined action of ice 
 and water produces floods unparalleled at other seasons of the 
 year. K this is the case upon the melting of the small amount 
 of snow which annually accumulates in our present winters, 
 the floods at the breaking up of the Glacial period itself 
 must have been iuconceivably great. With every recurring 
 spring we now look in the telegraphic summary for thrilling 
 accounts of ice-gorges formed in the St. Lawrence, the Dela- 
 ware, the Susquehanna, and the Missouri River. By reason 
 of these gorges, and their accompanying destructive floods. 
 Port Jervis, on the Delaware, and Mandan, on the Missouri, 
 have become famihar names. Reasoning from the nature of 
 the case, what, then, must have been the scenes during the 
 last stages of the great Ice age, when, through the months 
 of July, August, and September, warm southerly winds and 
 a glowing sun were combining to dissolve, with utmost ra- 
 pidity, the vast masses of ice which still lingered in the 
 country ! The channels were then compelled to carry off 
 not only the annual precipitation, and the torrents of an oc- 
 casional cloud-burst, but the stored-up precipitation which 
 had been accumulating as glacial ice for thousands of years. 
 
 Nor is this altogether theoretical. Though we have no 
 
dhajnaoe of the glaoial period. 315 
 
 telegraph to span the distances of time separating us from 
 those events, we have come into possession of signs as intel- 
 ligible as the lines and dots of the Morse alphabet, and even 
 more trustworthy. These floods along the lines of glacial 
 drainage have left their marks, and their direction and ex- 
 tent can be traced almost as readily as in the case of the 
 present streams. 
 
 Ascending the channel of the Mississippi above its junc- 
 tion with the Ohio, one enters a region where it is bordered 
 on each side by rocky bluffs, and finds himself in a valley of 
 erosion whose main features were determined in preglacial 
 times. Above Grand Tower, in southern Illinois, and as far 
 north as St. Louis (a distance of about one hundred and fifty 
 miles), the extreme margin of glacial deposits rests upon the 
 east side of the river, and an unglaciated region is upon the 
 west ; the width of the eroded valley being from five to ten 
 miles, and its depth several hundred feet. Above St. Louis 
 the valley gradually narrows, though it is still from two to 
 eight miles in width, and about the same depth as below the 
 city. At various places, along the sides of this eroded val- 
 ley, the observer will find gravel terraces one or two hundred 
 feet above the present fiood-plain. These terraces are, in 
 fact, the high- water mark of the closing floods of the Ice age. 
 
 But the culmination of interest is reached on coming to 
 the present junction of the Minnesota and Mississippi Riv- 
 ers near St. Paul. From Fort Snelling, just above St. Paul, 
 northward, the present Mississippi Eiver is a comparatively 
 recent stream, occupying a post-glacial bed. The true exten- 
 sion of the trough of the Mississippi follows up the Minne- 
 sota River. The gorge of the Mississippi, leading from Fort 
 Snelling up to Minneapolis, is scarcely a quarter of a mile in 
 width, and is about two hundred and fifty feet in depth ; 
 while the trough of the Minnesota is from one to four miles 
 in width, and its rocky bottom is more than one hundred and 
 fifty feet lower than the present bed of the stream. In the 
 bottom of this broad valley, for a distance of two hundred 
 and fifty miles, the Minnesota River wanders about from 
 
316 THE ICE AGE IN NORTH AMERICA. 
 
 eide to side as a very insignificant thing, entirely out of pro- 
 portion to the valley which it occupies. Nor does the Min- 
 nesota River have its sources in the highlands, like the Mis- 
 sissippi. Its head is in Big Stone Lake, in the midst of this 
 eroded trough, and but a few miles south of Lake Traverse — 
 the head of the Red Kiver of the North — also in the same 
 trough and on the same absolute level. The water from Lake 
 Traverse sometimes flows into the other lake. In short, the 
 troughs of the Minnesota and the Ked River of the North 
 are one and continuous, and the depression joining them, 
 known as Brown's V^alley, is to the glacialist one of the most 
 interesting spots on the continent. The following is Mr. 
 Upham's description : 
 
 Lakes Traverse and Big Stone are from one to one and a 
 half mile wide, mainly occupying the entire area between the 
 bases of the bluffs, which rise about one hundred and twenty- 
 five feet above them. Lake Traverse is fifteen miles long ; it 
 is mostly less than ten feet deep, and its greatest depth proba- 
 bly does not reach twenty feet. Big Stone Lake is twenty-six 
 miles long, and its greatest depth is reported to be from fifteen 
 to thirty feet. The portion of the channel between these lakes 
 is widely known as Brown's Valley. As we stand upon the 
 bluffs here, looking down upon these long and narrow lakes in 
 their trough-like valley, which extends across the five miles 
 between them, where the basins of Hudson Bay and the Gulf 
 •of Mexico are now divided, we have nearly the picture that 
 was presented when the melting ice-sheet of British Americn 
 was pouring its floods along this hollow. Then the entire ex- 
 tent of the valley was doubtless filled every summer by a river 
 which covered all the present areas of flood-plain, in many 
 places occupying as great width as these lakes.* 
 
 Among the most interesting facts concerning the drainage 
 lines of the glacial period are those connected with the 
 
 * " Proceedinga of the American Association for the Advancement ot Sci- 
 ■ence," vol. xxxii, 1883, pp. 216, 217. This glacial outlet through Brown's Val- 
 ley and the Minnesota has been fittingly named, by Mr. Upham, Eiver Warren 
 after General G. K. Warren, who first described it. See map in Chapter XXI. 
 
DRAINAGE OF THE GLACIAL PERIOD. 317 
 
 advance and recession of the ice from the basin of the Great 
 Lakes. As the advancing ice closed up the outlets leading 
 into the St. Lawrence Valley the drainage was successively 
 turned through Lake Champlain into the Hudson. A little 
 later it was turned ' around the Adirondacks through the 
 Mohawk River Valley into the Hudson. Later still it was 
 turned over into the Susquehanna through the fissures now 
 occupied by the Finger Lakes of Central New York. A still 
 farther advance turned the vast current through the valley 
 occupied by the Grand, Mahoning and Beaver rivers into the 
 head-waters of the Ohio and helped in the formation of its 
 present tortuous channel. 
 
 Meanwhile the advance of the ice farther west was produc- 
 ing numerous changes in the drainage of the upper lake region. 
 At first the drainage of Lakes Erie and Huron was turned 
 through the straits of Mackinaw into Lake Michigan and ran 
 off through the line of the present drainage canal into the 
 Mississippi through the Ilhnois River. Then, as soon as the 
 eastern end of Lake Superior was closed up, the drainage from 
 the western portion was through the St. Croix River at an 
 elevation of 466 feet above the lake into the Mississippi a 
 little below St. Paul. With the advance of the ice a little 
 further into the southern peninsula of Michigan the channel 
 through the Straits of Mackinaw was closed, forcing the water 
 over a low col leading from Saginaw Bay into the head- waters 
 of Grand River, and thence into Lake Michigan a short 
 distance below Grand Rapids, and so again over the line of 
 the Chicago drainage canal into the Mississippi basin. 
 
 A still further advance closed up the entire passage into 
 Lake Michigan and turned the drainage southward from 
 Toledo, Ohio, through the pass at Fort Wayne, Indiana, into 
 the Wabash River and thence into the Ohio. 
 
 Of course the direct evidence of these facts is not now 
 available, since the advancing ice has obliterated the beaches 
 and terraces which were built up before it. But on the retreat 
 
ft 
 
 DRAINAGE MAP 
 
 , -F OP 
 
 9.^feV^ SOUTHEASTERN 
 
 I OWA 
 
 by 
 
 Frank Leverett. 
 
 toot 
 
 Rq. 97. — Cross section of the Osage trough at Tuscumbla, Mo., with a Canadian 
 bowlder on the upper terrace above the flood plain. (See p. 321) . 
 
DRAINAGE OF THE GLACIAL PERIOD. 319 
 
 of the ice these lines were opened in reverse order and shore 
 lines and abandoned channels were left for inspection for all 
 time. These abandoned channels and the bordering high- 
 level gravel terraces are clearly marked through the line of 
 the St. Croix River in Wisconsin, through the line of the Chi- 
 cago drainage canal, through the pass at Fort Wayne and 
 along the whole course of the Wabash River in Indiana, and 
 to a greater or less extent through the other passes which 
 were occupied by the reversed glacial floods for a shorter 
 time further east. The shore lines of the temporary glacial 
 lakes whose levels were determined by the height of these 
 several passes are also clearly marked around the west end of 
 Lake Superior in the terraces above Duluth; and around 
 the southern shore of Lake Erie where at three levels already 
 mentioned they lead to Fort Wayne, at an elevation of 200 
 feet above the present level of the lake, and from Saginaw Bay 
 at levels of 150 and 100, respectively, to the upper and the 
 lower passes into Grand River, Michigan. 
 
 Mr. Frank Leverett discovered a most interesting dis- 
 placement of a middle portion of the Mississippi River dur- 
 ing the farthest advance of the Illinoisan ice-sheet, which 
 pushed across the river for an average distance of from 
 thirty to forty miles between Clinton and Keokuk. This 
 forced the drainage along the border of the ice-sheet through a 
 channel still clearly marked through Jackson, Clinton, Scott, 
 Muscatine, Louisa, Des Moines, Henry, and Lee counties, 
 a distance of about 150 miles. But on the retreat of the ice, 
 the present channel was opened. 
 
 Gravel terraces of great prominence also mark the course 
 of final glacial drainage through the Mohawk River in Cen- 
 tral New York, and a shore line aroimd the southern side of 
 Lake Ontario is distinctly traceable from the mouth of the 
 Niagara gorge to the col at Rome, leading from the Ontario 
 basin into the Mohawk. 
 
320 THE ICE AGE IN NORTH AMERICA. 
 
 Another striking deposit of this final glacial drainage can 
 be seen on the eastern flank of the Adirondack Mountains 
 at Chazy, a few miles west of Plattsburgh, where there is a 
 large and most remarkable accumulation of rolled river 
 pebbles two or three hundred feet above the level of Lake 
 Champlain, while there is no stream bed anywhere near 
 this locality. The only explanation of it is (and it is entirely 
 adequate), that this was a line of temporary drainage for the 
 glacial floods which for a time accumulated in the upper 
 St. Lawrence Valley and found their only passage for a while 
 between the mountain mass of the Adirondacks and the wan- 
 ing ice which filled the Champlain Valley. (For an illustra- 
 tion from Alaska, see Plate VIII.) 
 
 From the Missouri Valley there come some of the most 
 startling facts revealing the extent of the floods which charac- 
 terized the later stages of the glacial period. The present 
 Missouri discharges (according to Humphreys and Abbott) 
 twenty-nine cubic miles of water armually. Yet, even so, 
 there are frequently floods in the lower part of the valley 
 which reach a height of thirty or forty feet above present 
 low water mark. But at the time of the greatest extent of 
 the ice-sheet the drainage of not far from 250,000 square 
 miles of ice covered area found its way into the Middle Mis- 
 souri. For a considerable time towards the close of the 
 glacial epoch the ablation of this ice would, at a moderate 
 estimate, amount to ten feet per annum over this wholq 
 contributory surface. This would furnish 500 cubic miles of 
 additional water to be carried off through the lower portion 
 of the river channel during each summer between April and 
 November. An examination of the lower channel shows that 
 at Hermon twenty-five miles below the mouth of the Osage 
 River where it joins the Missouri the passage between rocky 
 bluffs 300 feet high is barely two miles wide. Mathematical 
 calculations will show that it would require ninety-six days 
 for a current two miles wide and two hundred feet deep, flow- 
 
DRAINAGE OF THE GLACIAL PERIOD. 321 
 
 ing at the rate of three miles an hour, to carry off this surplus 
 drainage of 500 cubic miles accumulating each summer. 
 
 If it should be supposed that the current would be much 
 faster than three miles an hour, it is proper to note that 
 from the known facts about the northerly depression of the 
 land during the latter part of the glacial period it is extremely 
 probable that the gradient of the stream was very much 
 less during the time of these floods than it is now. Further- 
 more, the gradient of the stream was much diminished by the 
 flooded condition of the Mississippi into which the Missouri 
 enters. For, the glacial floods pouring into the Mississippi 
 and Ohio were of such enormous magnitude as probably to 
 raise the level of the Mississippi 100 feet or more, during these 
 summers. It is not at all unreasonable, therefore, to expect 
 to find indications of glacial floods in the Lower Missouri 
 rising to a height of 200 feet or more. 
 
 And these we do find. In 1902, Dr. Ball of the Missouri 
 Geological Survey found a number of large Canadian bowlders 
 in the valley of the Osage River sixty miles above its junction 
 with the Missouri and forty miles south of the extreme limit 
 of the extension of glacial ice. There is no way to account for 
 such bowlders in that position except on the supposition 
 that they were floated in there by a backward current from 
 the Missouri when its glacial floods, bearing floating masses of 
 ice with Canadian bowlders upon their surface, reached a 
 height of 200 feet. Since there was no melting ice in the valley 
 of the Osage to increase its volume, such an eddy in the cur- 
 rent would be sure to set up that valley and supply the cause 
 necessary to explain what was a very puzzling problem when 
 first propounded. Such floods also are needed in the Missouri 
 Valley to account for the many level-topped extensive accu- 
 mulations of loess (a fine river loam to be described more in 
 detail in a later chapter) which occur at numerous points 
 throughout the valley. 
 
Fio. 98. — The unshaded portion shows the glaciated area; but at Tuscumbia numeroua 
 
 Canadian Ijowldersare found In the upper gravclterraces bordering the Osage river. 
 (See fin. 97, p. 318.) Tliese could have come into this place only by the agency of 
 back waterbearing Ice floes from the glacial floods of thcMisyouri as described tn 
 the text. 
 
DRAINAGE OF THE GLACIAL PERIOD. 323 
 
 The high level gravel terraces so constantly lining 
 the water-courses in the Middle and Western States, and 
 which formerly were attributed to the advance into these 
 regions of the waters of the ocean, are readily accounted for 
 by the action of the torrents set free by the melting of the 
 ice during the closing years of the great Ice age. One of the 
 striking confirmations of the glacial theory appears in the 
 absence of terraces in the valleys of such minor streams as 
 have their sources south of the glacial limits. For example, 
 in Ohio the small streams in the southeastern part of the 
 State, whose sources are outside of the glacial limits, present 
 a marked contrast to the other streams of the State flowing 
 south, as do also the streams flowing to the north and empty- 
 ing into Lake Erie. The troughs of the Wabash, the two 
 Miamis, the Scioto, the Hocking, and the Muskingum, with 
 their tributaries, are all Unfed by gravel terraces, rising from 
 fifty to one hundred and fifty feet above the present flood- 
 plains, showing the enormous volume of the streams which 
 flowed through them at the close of the period. The coarse- 
 ness of the material in these terraces also bears witness to the 
 violence of the currents. But between the mouth of the 
 Muskingum, at Marietta, and the mouth of the Libtle Beaver, 
 the streams entering the Ohio are devoid of terraces, the ex- 
 planation being that their sources lie outside of the glaciated 
 limit, so that they had access neither to the accumulations of 
 the glacial deposits, which furnished material for the terraces, 
 nor to the floods of water that distributed it. To the east- 
 ward, again, upon striking the streams whose drainage-basins 
 lie within the glaciated limit, high terraces, containing north- 
 em pebbles brought from beyond the water-shed, begin again 
 to appear, both along the margins of the streams in the gla- 
 ciated area, and also through their whole course below the 
 boundary. In the matter of terraces, likewise, the northern 
 tributaries of the Ohio are in striking contrast with the 
 southern. 
 
 East of the Alleghanies the same contrast appears between 
 the streams rising within the glaciated area and those outside 
 
DRAINAGE OF THE GLACIAL PERIOD. 325 
 
 of it. The terraces on the East Branch of the Susqxiehanna are 
 mtich more marked than those upon the West Branch, the 
 explanation being that the East Branch lies almost wholly 
 within the glaciated area, while only a few of the minor tribu- 
 taries of the West Branch* come down from it. But wherever 
 they do so come, as in the case of Pine, Lycoming, and Loy- 
 alsock Creeks, a limited amount of drift from the far north 
 is distributed along their banks, and deposited at their junc- 
 tion with the main branch of the river. The Lehigh and the 
 Delaware are likewise marked by high terraces containing 
 pebbles from the far north, while the Schuylkill River, which 
 lies just outside of the glaciated limit, has no such terraces. 
 Thus, both by the method of agreement and of difference, we 
 prove the connection of these terraces of the so-called " Ter- 
 race epoch " with the gorged and gravel-laden streams of the 
 great Ice age. 
 
 Before speaking of the lines of glacial drainage, farther 
 east, it will be profitable to direct our attention to another 
 class of closely connected facts confirming the theory of the 
 glacial origin of these terraces. The larger part of the ma- 
 terial contained in them is derived from the glacial deposits 
 over the region through which the several streams flow. The 
 hard fragments of granite, quartzite, and various metamorphic 
 rocks from the region of Lake Superior and the Canadian 
 highlands are eminently fitted to withstand abrasion, and can 
 be rolled by a torrent for long distances before being ground 
 to powder, while the softer sandstones and shales of the newer 
 geological formations would be comminuted by the attrition 
 of a comparatively few miles' travel. Hence it comes about 
 that the terraces of the Middle States are composed, in a pre- 
 dominant measure, of material brought over the water-shed 
 by the ice from the far north, and spread broadcast over the 
 country, and thence collected by the streams of water and 
 rolled along as far to the south as there was force in the cur- 
 rent to move them, or through as great a distance as the 
 hardness of the material of which they are composed would 
 enable them to resist complete attrition. There is no more 
 
326 THE lOE AGE IN NORTE AMERICA. 
 
 interesting verification of an hypothesis anywhere to be found 
 than that furnished for the glacial theory through the study 
 of the character of some of these terraces at and below the 
 glacial limit. Theoretically the terraces should, for the rea- 
 sons just stated, be more promineilt and consist of coarser 
 materialj just where the streams emerge from the glacial 
 limit ; and such, from a wide collection of facts, is proved to 
 be the rule. I have myself examined nearly all the streams 
 thus emerging from the glaciated area between the Atlantic 
 Ocean and the Mississippi River.* In scores of places where 
 streams thus emerge from the glaciated region — in Pennsyl- 
 vania, Ohio, and Indiana — their valleys are filled with an 
 accumulation of water-worn northern drift, which, when fol- 
 lowed downward, becomes gradually less in amount, as well 
 as more water-worn, and finer in its constituent elements. 
 
 This is notably the case in the Delaware Valley, at Belvi- 
 dere, !N., J. ; in the Susquehanna, at Beach Haven, Pa. ; in 
 the Cpnewango (as already described), at Ackley, Warren 
 county ; in Oil Creek, above Titusville ; in French Creek, 
 a little above Franklin ; in Beaver Creek, at Chewtown, Law- 
 rence county ; on the Middle Fork of Little Beaver, near 
 New Lisbon, Ohio ; on the east branch of Sandy Creek, at 
 East Rochester, Columbiana county ; on the Nimishillin, at 
 Canton, Stark county ; on the Tuscarawas, at Bolivar ; on 
 Sugar Creek, at Beech City ; on the Killbuck, at Millersburg, 
 Holmes county ; on the Mohican, near the northeast comer 
 of Knox county ; on the Licking Eiver, at T^ewark ; on 
 Jonathan Creek, Perry county ; on the Hocking, at Lancas- 
 ter ; on the Scioto, at Hopetown, just above Chillicothe ; on 
 Paint Creek, and its various tributaries between Chillicothe 
 and Bainbridge ; and on the Wabash, above New Harmony, 
 Ind. ; to which may be added the Ohio Eiver itself, at its 
 junction with the Miami, near Lawrenceburg. 
 
 Some of these instances are sufficiently interesting and 
 
 * " Glaciated Area of Ohio," iu the " American Journal of Science," toU 
 cxxvi, 1883, pp. 1-14; "American Naturalist," vol. xviii, pp. 755-767. 
 
DRA-INAOE OF THE OLACIAL PERIOD. 327 
 
 instructive to warrant a special description. The iipper part 
 of the Ohio River, between Pittsburg and New Eichmond, 
 in the vicinity of Cincinnati, lies entirely outside of the gla- 
 ciated area, while nearly all of its northern tributaries rise 
 within that area. In the happy phraseology of Professor 
 Dana, the Ohio River becomes, therefore, the great distribu- 
 ter, while its northern tributaries are the principal contribu- 
 tors., of terrace material. Now, it is observable that, wherever 
 a large contributor of drift material comes in from the north, 
 . there is a great increase in the extent and height of the ter- 
 races for some distance below, and the material of which the 
 terrace is composed is coarser at these points. For example, 
 in the neighborhood of Cincinnati, the Ohio is joined by the 
 Little Miami, and twenty miles below, at Lawrencebiirg, by 
 the Great Miami. Throughout their entire course these 
 tributary streams flow through a region deeply covered with 
 glacial deposits. As a consequence, the terraces here are of 
 great height and width. At Cincinnati, the upper terrace 
 upon which the original city is built is one hundred and 
 twenty feet high; and at Lawrenceburg the valley, from 
 three to four miles wide, is nearly tilled to a height of one 
 hundred and twelve feet above the flood-plain, with a ter- 
 race deposit clearly derived from the glacial floods of the 
 Great Miami and its tributaries. Below this point the ter- 
 races of the Ohio gradually diminish in height, and the ma- 
 terial becomes finer, and more and more water-worn. Above 
 Cincinnati there is a marked development of the terraces at 
 the mouth of the Scioto, at Portsmouth ; and again, below 
 Marietta, at the mouth of the Muskingum, where, opposite 
 Blennerhassett Island, the terraces are in the neighborhood 
 of one hundred feet above the present low-water mark. It 
 is to be noted that both of these streams were so situated as 
 to be among the largest contributors to the Ohio, both of 
 glacial floods and glacial debris. 
 
 But the most instructive place for the observation of this 
 class of phenomena is to be found in Pennsylvania, at the 
 junction of Beaver Creek with the Ohio River. From the 
 
328 THE ICE AGE IN NORTH AMERICA. 
 
 mouth of Frencli Creek, at Franklin, Pa., to the month of 
 Beaver Creek, twenty-five miles below Pittsburg, a distance 
 of about one hundred and fifty miles, no contributors of gla- 
 cial material enter the Alleghany or the Ohio River, and the 
 course of the river-bed lies wholly in the soft, sedimentary 
 deposits of the coal-measures. Consequently, while this por- 
 tion of the stream contains terraces with northern drift 
 brought into the Alleghany above Franklin, they are of 
 diminishing height, and contain a constantly diminishing 
 amount of material from the glacial drift all the way down 
 to the mouth of the Beaver. 
 
 At the mouth of the Beaver there is a sudden enlarge- 
 ment of the Ohio terrace, and it rises at once to a height of 
 one hundred and twenty feet above the river. Upon the 
 lower side of the Beaver, in the angle between it and the 
 Ohio, down-stream, this terrace is very extensive, and the 
 material very coarse, the terrace being, indeed, largely built 
 up of pebbles and bowlders from a few inches to two feet 
 or more in diameter, and all thoroughly rounded. On the 
 opposite side of the Beaver, in the angle between its mouth 
 and the upper portion of the Ohio, there is, for a limited 
 distance, a terrace of equal height, but of entirely different 
 composition from that upon the lower side. The terrace 
 upon the upper side consists of fine material, being mostly 
 sand and gravel derived from the coal-measures, through 
 which the Ohio itself has cut its way. Pebbles from the 
 northern drift are rare, and the local origin of the material 
 is manifest at a glance. What, now, makes this difference 
 between these terraces upon the opposite sides of this small 
 tributary of the Ohio ? A glance at the map will show.* 
 
 The Beaver River emerges from the glaciated region only 
 a few miles to the north of its junction with the Ohio. The 
 larger part of its drainage-basin lies in portions of northeast- 
 em Ohio and northwestern Pennsylvania, which are deeply 
 covered with the terminal deposits of the continental ice- 
 
 * Sec map, p. 145. 
 
DRAINAGE OH' THE GLACIAL PERIOD. 329 
 
 sheet. The floods characterizing that period had access to 
 an unlimited amount of material, which was easily swept into 
 the current, and rolled down the torrential bed toward the 
 Ohio Elver. Upon reaching the Ohio, the combined cur- 
 rent of the two streams in the larger valley would have far 
 less power of transportation than the constricted current in 
 the channel nf the glacial tributary. The bowlders would, 
 therefore, be deposited at the mouth of the Beaver, where it 
 joins the Ohio, and, owing to the influence of the current of 
 the Ohio itself, would be carried below the junction of the 
 two rivers. Hence it is that we find so many glacial bowl- 
 ders below the junction, and so few above it. The accumu- 
 lation of a terrace of an equal height above the junction, but 
 consisting of fine and local material, is also what would be 
 required by theory as well as what is found to be the case in 
 fact. Thus we have, in this single instance, one of the best 
 possible verifications of the glacial hypothesis. 
 
 Of the glacial terraces on the Delaware River, from the 
 Water-Gap to Trenton, N. J., there will be occasion to speak 
 more fully when treating of the subject of man's relation 
 to the Ice age in North America. Nor can we more than 
 allude to those which line the Mohawk and the troughs of the 
 Hudson and its tributaries. It is sufficient to say that the 
 passengers upon the New York Central Railroad can satisfy 
 themselves of the existence of these terraces east of Little 
 Falls, N. Y., and between Schenectady and Albany, by 
 merely looking out of the car-windows toward the north ; 
 and a moment's reflection upon the topography of the coun- 
 try will show that the terraces of the Mohawk and the up- 
 per Hudson are much more recent than those of the Susque- 
 hanna and the Delaware, since glacial streams could not have 
 occupied the Mohawk until after the ice-front had retreated 
 from northeastern Pennsylvania and the highlands of south- 
 ern New York, in which the drainage-basins of the Susque- 
 hanna and the Delaware River are situated. When, there- 
 fore, the glacial floods of the Mohawk were at their height, 
 the Delaware and the Susquehanna had been relieved of 
 
330 THE ICE AGE IN NORTH AMERICA. 
 
 their excessive burdens, and had subsided to something like 
 their present volume. 
 
 As illustrating the capacity of the glacial theory to ex- 
 plain the otherwise unaccountable facts connected with the 
 recent changes in the drainage of the glaciated region, atten- 
 tion is directed to two or three interesting localities east of 
 the Alleghanies, where the dry beds of abandoned streams 
 have been discovered. 
 
 We will first consider the outlets of an interesting glacial 
 lake which temporarily occupied the upper part of Contocook 
 Valley in Hillsborough county, N. H., the details concerning 
 which were furnished as early as 1878 by Mr. Upham, in 
 the New Hampshire Geological Report. The Contocook 
 River now empties into the Merrimack a little above Con- 
 cord, and flows in a direction north-northeast. As a conse- 
 quence, the present outlet was, toward the close of the Gla- 
 cial period, obstructed by ice some time after it had melted 
 off from the southeastern portion of the valley. During that 
 period a lake was held in the portion of the valley freed 
 from ice, at a height sufficient to turn the drainage tempo- 
 rarily to the south and southeast. At first the drainage was 
 over the water-shed in Rindge, through Ashburnham and 
 Winchendon, Mass., and thence into the Connecticut. The 
 reality of this line of drainage is evidenced by the exten- 
 sive kames and gravel deposits extending from the Conto- 
 cook Valley through the towns of Rindge and Winchendon. 
 When the ice had withdrawn a little farther north, an outlet 
 was open to the southeast into the Souhegan River, and 
 thence into the Merrimack. The evidence here is also con- 
 clusive that, for a period, a stream of water eighty feet deep 
 poured through this pass, and the lake formed in front of 
 the ice was in its greatest extent thirty miles long, and from 
 two hundred to two hundred and fifty feet in depth. The 
 evidence of this remains in delta terraces at that level 
 formed at various points where streams came into the lalte. 
 
 Another instance is in Grafton county, N. H., on the line 
 of the Northern Railroad, between Grafton Centre and East 
 
DRAINAGE OF THE GLACIAL PERIOD. 331 
 
 Canaan, on the water-parting between the Merrimack and 
 the Connecticut, where there is to be found the dry bed of a 
 river which for a time flowed through a pass from the Con- 
 necticut Valley into the Merrimack, but which is five hun- 
 dred feet above the valleys. Here upon this mountain axis, 
 in central New Hampshire, nine hundred feet above the sea, 
 are numerous and large water-worn circular cavities in the 
 rock, technically known as pot-holes, such as are formed in 
 shallow rapids, wherever gravel and pebbles become lodged, 
 first, in some natural slight depression, and then, through the 
 whirling motion given them by the running ■ water, these 
 continue to wear a symmetrical depression so long as the 
 supply of water continues, or until a channel has been cut 
 through. Pot-holes may be seen in the rapids of almost any 
 rocky stream, with the gravel and pebbles, which do the im- 
 mediate work when set in motion, still partially filling them. 
 Such pot-holes exist in the anomalous position mentioned in 
 New Hampshire, where no present stream could by any pos- 
 sibility be made to fiow. One of them, measured many years 
 ago by Jackson, was eleven feet deep, four and a half feet in 
 diameter at the top, and two feet at the bottom, and, when 
 discovered, was tilled with earth and rounded stones.* 
 
 The explanation of this phenomenon furnished by Mr. 
 Upham, while engaged on the New Hampshire Survey, is as 
 follows : The ice of the Connecticut Valley, being farther 
 from the glacial front, lingered considerably longer than that 
 in the Merrimack Valley to the southeast, so that for a con- 
 siderable period the drainage from the ice-front in the south- 
 eastern part of Grafton county was compelled by the ice- 
 barrier on the west to flow over this depression into the Mer- 
 rimack basin, thus furnishing exactly the conditions neces- 
 sary for the production of pot-holes and such other marks of 
 water-action as have so long puzzled geologists at this point. 
 
 Similar pot-holes, to be accounted for in like manner, 
 have recently been described near Archibald, in Blakely 
 
 * " New Hampshire Geological Report," vol. iii, pp. 63-66. 
 
332 THE ICE AGE IN NORTH AMERICA. 
 
 township, Lackawanna county, Pa.* The principal one is 
 from fourteen to seventeen feet in diameter at the top, and 
 is forty feet deep — the sides being very smooth. The de- 
 pression is worn through strata of sandstone, shale, and coal. 
 The pebbles which did the wearing were still in the bottom 
 of the hole when it was discovered, and are mostly of foreign 
 origin, though some of them consisted of pebbles cut from 
 the coal-bed itself. The elevation is eleven hundred and 
 twenty-niuefeet above tide, and no explanation seems possible 
 except that which assumes that a stream of water was kept 
 running in that position for a limited period by ice-barriers. 
 
 In passing, it is interesting to remark that the study of 
 the glacial deposits in the coal region becomes of great prac- 
 tical interest from the relation of their buried channels to 
 mining industries. Not only is there money to be saved by 
 knowing the depth of the till, and the inequalities of its 
 distribution, but the lives of the miners are seriously jeopard- 
 ized by ignorance upon this point. On December 18, 1885, 
 at Nanticoke, near the vicinity of the pot-hole just de- 
 scribed, one of the most shocking mining disasters on record 
 occurred, from miscalculating the course of a buried pre- 
 glacial channel, which was penetrated by the miners in an 
 unexpected place, causing a flood of quicksand, mud, and 
 bowlders to fill the mine and immolate twenty-six miners 
 beyond hope of rescue. 
 
 Another instance of glacial drainage worthy of record is 
 reported by Professor J. E. Todd from the Missouri cotean 
 in Dakota. Crow Creek flows westward, and enters the Mis- 
 souri in Buffalo county, heading well in the terminal mo- 
 raine ; t 
 
 Two of its principal branches lead us into the heart of 
 the great interlobular moraines, the Kees, and the range of 
 which Turtle Point is the head, then by unmistakable channels 
 ihrouffh them to the inner side of the moraine and out upon 
 
 * " Annual Report of the Pennsylvania Geolo^cal Survey," 1885, pp. 
 615-620. t See map, p. 216. 
 
DRAINAGE OF THE GLACIAL PERIOD. 333 
 
 the great ice-sheet itself. It produces strange sensations to 
 pass up those dry, flat-bottomed valleys, with a steep bank on 
 either hand fifty to one hundred and fifty feet in height, 
 almost built of bowlders ; huge cones of gravel, evidently 
 formed in ancient eddies, here and there in the valley ; simi- 
 lar valleys joining it now and then. You press on, wondering 
 where the beginning can be, for your map tells you that there 
 are streams which must cut right across its course if it con- 
 tinues as far as you might judge from its width. You press on 
 eagerly, you note the banks rapidly subsiding, but the channel 
 you tread still preserves its gradual rise, then suddenly you 
 come out upon the face of the range, and a magnificent view 
 of the plain, two hundred to three hundred feet below, bursts 
 upon you. You look for the inclined plane which by easy 
 steps has brought you to this altitude, and find it ending 
 abruptly with the face of the hills. You realize, as never 
 before, the mass of ice which once must have occupied the 
 expanse before you. You can see that stream, scores of yards 
 in width, leaving its icy banks, now vanished in thin air, for 
 the stony ones which still remain.* 
 
 It seems clear, also, that the disturbing effects of the great 
 ice-sheet upon the drainage of the Northwest will account 
 for the numerous deserted river- valleys described by Dr. 
 G. M. Dawson in the part of British America lying between 
 the Lake of the Woods and the Kooky Mountains. Here 
 the conditions were somewhat peculiar. The natural drain- 
 age is down the flanks of the Rocky Mountains eastward to 
 the Eed River Valley. The Saskatchewan River drains the 
 northern portion of the territory, while the Assiniboin with 
 its branches, the Qu'Appelle and Souris, drains the southern 
 portion — the drainage-basin of the Souris joining that of the 
 Mi?souri in Dakota. The Pembina River, a much smaller 
 stream, empties into the Red River near the boundary-line, 
 considerably south of the Assiniboin ; and the Sheyenne still 
 farther south. 
 
 * " Proceedings of the American Association for the Advancement of Soi- 
 ce," vol. xxxiii, 1884, p. 391. 
 
334 THE ICE AGE IN NORTH AMERIOA. 
 
 With the interpretation which the present discussion has 
 put upon the facts, the following is the order of events : Dur- 
 ing the farthest extension of the ice to the vicinity of the Eocky 
 Mountains, the South Saskatchewan was compelled to flow 
 around the front of th^ ice-sheet to join the Milk Eiver at 
 the boundary-line near the one hundred and tenth meridian, 
 and thence into the Missouri. A great dry coulee, a portion 
 of which is occupied by a large saline lake known as Peeko- 
 pee, is a marked feature connecting these streams at the 
 present day.* 
 
 Coming eastward to the one hundred and second meridian, 
 the Riviere des Lacs seems, without doubt, to have been the 
 line of drainage for the Souris Eiver for a distance of sev- 
 enty-five or eighty miles. Characteristically enough, this 
 ends northward, near the Souris Eiver, "in a broad dry 
 coulee, which shallows and dies away in a strip of bowlder- 
 covered ground, which stretches northward toward the Souris 
 Eiver, live miles distant, and is somewhat lower than the 
 general surface of the plain." 
 
 At this time there was a lake-like expansion of water in 
 the Elbow of the Souris, covering Eenville, Ward, and Mc- 
 Henry counties, Dakota, the evidence of which is still plainly 
 seen. This lake, again, was forced to seek a southern outlet, 
 which it found through a coulee in McHenry county into 
 the head of the Sheyenne Eiver, and thence followed its 
 winding course to Lake Agassiz, near Fargo, where there is 
 an immense delta of river gravel. 
 
 Coming still farther east, the Pembina Eiver occupies a 
 valley very much larger than its present demands ; and, at 
 its junction with the Eed Eiver, there is also an immense 
 gravel delta, indicating it as a line of drainage at one time of 
 a far larger area than now. Upon following the valley of 
 the Pembina up, it is found to continue through the Pelican 
 Lake to the Elbow of the Souris, near the one hundredth 
 
 * " Report on the Geology and Resources of the Region in the Vicinity of 
 the Forty-ninth Parallel," pp. 262-268. 
 
DRAIN AGE OF THE GLACIAL PERIOD. 
 
 335 
 
 meridian, and twenty-live or thirty miles south of the As- 
 siniboin. Professor Hind finds evidence that this was the 
 outlet temporarily not only of the Assiniboin but, through 
 the Qu'Appelle and the River that Turns, to the South Sas- 
 katchewan. Mr. Upham writes me that he has followed this 
 old valley for one hundred and twenty-five miles as far as 
 Birtle, in Manitoba. According to Professor Hind, the 
 length of the valley of the Qu'Appelle, from Birtle up to 
 the Saskatchewan, is two hundred and sixty-eight miles in 
 direction northwest by southeast. The valley is uniformly 
 about one mile wide, and from one hundred and ten to three 
 hundred and fifty feet below the general level, and eighty- 
 five feet above the present level of the South Saskatchewan, 
 the descent being four hundred and forty feet from the 
 Saskatchewan to the Assiniboin. The inclosing bluffs con- 
 sist mainly of till, and the whole trough is characterized by 
 numerous long, shallow lakes. These lines of marginal drain- 
 age are readily explained upon the glacial hypothesis here 
 maintained, and are a strong proof of that hypothesis. As the 
 ice receded, more northern outlets were opened, and these 
 temporary channels were naturally abandoned. 
 
 Via. 100 — Map of South Dakota showing the extent to which the channel of the Missouri 
 River was permanently changed during the early Wisconsin epoch. The broken 1 ines 
 Indicate theformercourseof the Grand, Cheyenne, and White Rivers as they joined 
 theorlglnal Missouri when flowing through the James River valley. (Map by Todd.) 
 
336 THE ICE AGE IN NORTH AMERICA. 
 
 According to Professor Todd the preglacial Missouri 
 River entered the valley of the James near its upper portion, 
 reaching its present channel at Yankton. Having filled this 
 valley, the advancing ice from the northeast obstructed the 
 mouths of the Grand, Moreau, Cheyenne, and White river 
 and, forcing the drainage in front of the ice across the cols 
 between these streams, gave rise to the present tortuous 
 channel across the State of South Dakota. Lake Arikaree 
 was one of the temporary results of this advance. Its shore 
 lines being clearly traced at a height of 400 feet above the 
 the present Missouri. The bowlders near the Moreau River 
 and the deserted river bed mentioned on pages 146 and 147 
 are connected with the existence of this lake. 
 
 Coming still farther southeast, we find that the Minnesota 
 River makes a sharp turn to the north at Mankato, and so is 
 favorably situated for having its drainage reversed while the 
 ice rested over the counties about its junction with the Mis- 
 sissippi near St. Paul. The facts are foimd to be according 
 to the programme. There is abimdant evidence of a, tempo- 
 rary lake, covering the territory of Blue Earth and Faribault 
 coimties, which emptied through a channel known as Union 
 Slough, about eight miles long and from one-eighth to one- 
 fourth of a mile wide, with bluffs from twenty to thirty feet 
 in height, which connect Blue Earth River with the Eastern 
 Branch of the Des Moines in Kossuth County, Iowa. 
 
 In this connection it is in place also to refer to the dramatic 
 history of Lake Bonneville during the Glacial Period, though 
 a fuller account will be necessary in future chapters (see 
 pages 615 and 703) . This body of water accumulating in the 
 basin of Great Salt Lake during the moist and cool climate of 
 that period attained a depth of 1,000 feet, covering an area 
 of 20,000 square miles. At this elevation there is a distinct 
 shore line traceable around the whole distance, broken into 
 occasionally by terminal moraines of the glaciers that came 
 down from the Wasatch mountains. Near the northeast 
 corner of the basin a dirt dam had been formed 375 feet high 
 
DRAINAGE OF THE GLACIAL PERIOD. 337 
 
 by the wash from the mountains on either side. This dam 
 separated the basin from the Port Neuf river which debouches 
 upon the Snake river plain at Pocatello. Evidently when the 
 opening was once made the whole body of water from the 
 upper 375 feet of Lake Bonneville poured down this little 
 valley in torrents which baffle all our descriptive powers. 
 Evidence of its torrential action are visible all along the 
 valley and especially at Pocatello where an immense bowlder 
 bed was deposited. (See figures on pages 615 and 703.) 
 
 Note to the Fourth Edition. — Since the following chapter upon 
 "Karnes" was written, a partially successful effort has been made to 
 distinguish between kames and eskers; but the distinction is not so 
 well defined as to make it necessary to rewrite the chapter. Accord- 
 ing to Professor Chamberlin (see Geikie's "Great Ice Age," third 
 edition, p. 746), eskers denote the long gravel ridges which conform in 
 general to the direction of the ice movement, while "kames take on 
 the form of bunchy aggregations of knolls and irregular ridges, and 
 have a tendency to arrange themselves in belts parallel to the margin 
 of the ice." But "it is not to be understood that any sharp line of 
 distinction can be drawn between the two types. They are connected 
 by intermediate forms which are difficult to place in either class. The 
 kames, as well as the eskers, are regarded as products of glacial drain- 
 age." 
 
CHAPTER XIY. 
 
 KAME8. 
 
 The word " kame " has already been defined as a local 
 term applied to the sharp gravel ridges which abound in 
 various parts of Scotland, and which in Ireland are called 
 "eskers," and in Sweden "osars." As Mr. Geikie's work 
 on " The Great Ice Age " has given currency to the Scotch 
 name, and as the word has been adopted by those who have 
 investigated this class of formations most fully in America, 
 it seems best to continue its use, though, either of the other 
 names is more euphonious. This class of ridges was first 
 described in this country in 1842 by President Edward 
 Hitchcock. Speaking of the gravel deposits in Andover, 
 Mass., known as Indian Ridge, he says they are " a collec- 
 tion of tortuous ridges and rounded and even conical hills 
 with corresponding depressions between. These depressions 
 are not valleys which might have been produced by run- 
 ning water, but mere holes, not unfrequently occupied by a 
 pond." * The fuller description of their composition by Mr. 
 James Geikie is as good for America as for Europe : 
 
 The sands and gravels have a tendency to shape themselves 
 into mounds and winding ridges, which give a hummocky and 
 rapidly undulating outline to the ground. Indeed, so charac- 
 teristic is this appearance, that by it alone we are often able to 
 mark out the boundaries of the deposits with as much precision 
 as we could were all the vegetation and soil stripped away and 
 
 * " Transactions of the American Association of Geologists and Naturalists," 
 1842. 
 
340 
 
 THE ICE AGE IN NORTH AMERICA. 
 
 the various subsoils laid bare. Occasionally, ridges may be 
 tracked continuously for several miles, running like great arti- 
 ficial ramparts across the country. These vary in breadth and 
 height, some of the more conspicuous ones being upward of 
 four or five hundred feet broad at the base, and sloping upward 
 at an angle of twenty-five or even thirty-five degrees, to a height 
 of sixty feet and more above the general surface of the ground. 
 It is most common, however, to find mounds and ridges con- 
 fusedly intermingled, crossing and recrossing each other at all 
 angles, so as to inclose deep hollows and pits between. Seen 
 from some dominant point, such an assemblage of kames, as 
 they are called, looks like a tumbled sea— the ground now 
 swelling into long undulations, now rising suddenly into beau- 
 tiful peaks and cones, and anon curving up in sharp ridges 
 that often wheel suddenly round so as to inclose a lakelet of 
 bright clear water.* 
 
 From this description it will be seen that there are some 
 remarkable resemblances between kames and terminal mo- 
 raines, since both of them are characterized by confused 
 hummocks and tortuous ridges of glacial debris, connected 
 with numerous bowl-shaped depressions, often containing 
 
 Fig. 102.— Section of kame near nover. New Hampshire. Length, three hundred feet ; height 
 forty feet ; base, about forty feet above the Cochecno River, or seventy-five feet 
 above the aea. a, a, gray clay ; 6, fine sand ; c, c, coarse gravel containing pebbles 
 from six inches to one foot and a half in diameter ; d, d, fine gravel. CUpham.) 
 
 lakelets. But in other respects there is a marked difEerenee 
 between them. In the first place, the material of which 
 kames are formed is ordinarily *rauch finer and more water- 
 worn, and shows more abundant signs of stratification than 
 that of which terminal moraines are composed. Secondly, 
 while the terminal moraine forms a ridge at right angles to 
 the motion of the glacier, and marks the limit of its exten- 
 
 » " The Great Ice Age," pp. 210, 211. 
 

 
 I s. 
 
KAME8. 
 
 341 
 
 sion during a prolonged period, the kames approximately 
 coincide in direction with the lines of glacial striae. A large 
 part of New England is covered with kaiue deposits, arranged, 
 in general, along the main lines of present drainage, with 
 merely such anomalous exceptions as can readily be ex- 
 plained by the interference which the ice itself offered to 
 the course of the floods which characterized the last stages 
 of the Grlacial period. 
 
 SOXJTH SIDE 
 
 NORTH SIDE. 
 
 Fig. 103. — Sections of a kame at Bennington Station, New Hampshire. Scale about forty feet 
 to the inch. The upper figure shows a simple transverse section ; the lower figure is 
 directly transverse on the right side, but longitudinal on the left. Counting from the 
 top the strata are ; 1, coarse yellow gravel, with pebbles up to eight inches in diame- 
 ter, thiclcness, three to five feet ; 2, fine sand, three to five feet ; 3, coarse, dark 
 gravel, containing pebbles np to one foot in diameter, three feet ; 4, fine sand, ob- 
 scured at the bottom by crumbling of the bank, fonr to eight feet ; a. a. downfall 
 of strata with irregular, broken, steep slope, against which lies an accumulation of 
 sand ; B, depression of two feet, similar to the foregoing ; f. fault, seen only on tlie 
 south side, dislocation of strata, six inches. (Upham.) 
 
 The most satisfactory conclusion with regard to the origin 
 of kames is that they mark, in the glaciated region, lines of 
 drainage during the closing stages of the Ice age. It is evi- 
 dent, from a moment's reflection, that the streams of water 
 resulting from the annual precipitation, combined with that 
 from the wasting of the ice during these closing stages, must 
 have been enormous, and may very likely have flowed in 
 channels quite different from those chosen after the ice had 
 completely melted away. Of course, these glacial streams 
 must, in the main, have followed the great valleys ; but 
 many of the minor valleys were, at that time, so obstructed 
 that the streams might disregard them and take a more di- 
 rect route over the ice through the open channels and long 
 tunnels which must then have existed. Those familiar only 
 
342 THE IGE AOE IN KOETH AMERICA. 
 
 with the contracted glaciers of the Alps are scarcely prepared 
 to appreciate the extent to which currents of water flow over 
 the larger glacial masses and rearrange and transport the su- 
 perficial material collected upon them. The " subglacial " 
 streams also are not always strictly subglacial, since they 
 often flow through tunnels which are midway between the 
 top and the bottom of the ice-mass. In the Muir Glacier, 
 Alaska, for example, the two streams issuing from the ice- 
 front near the sides of the glacier are several hundred feet 
 above the level at which the two streams emerge near the 
 center of the channel. There, also, streains of water of more 
 or less size can occasionally be seen pouring out from the 
 perpendicular front of the ice a hundred or more feet above 
 the surface of the inlet. Nor is it any uncommon thing to 
 see icebergs move off with water- worn tunnels in them 
 which are still well filled with gravel and pebbles. In the 
 various depressions in the surface of the glacier also, where 
 at times extensive lakes of water are formed, there is much 
 accumulation and assortment of earthy material far back from 
 the terminal margin of the glacier. 
 
 We will now endeavor briefly to reproduce the conditions 
 in New England near the close of the Ice age, in order to 
 see how the facts fit into the theory just enunciated. 
 
 The main north-and-south valleys of New England are 
 now drained by the St. John, the St. Croix, the Penobscot, the 
 Kennebec, the Androscoggin, the Merrimack, and thd Con- 
 necticut Rivers, with various smaller subordinate drainage- 
 basins, such as the Machias, the Saco, and the Piscataqua. 
 The larger valleys are also joined by various subordinate 
 ones, tributary to them, running in various directions con- 
 formable to the general contour of the country. But the 
 present course of the rivers is not necessarily determined 
 at every point by barriers of any great height. For exam- 
 ple, there are no high barriers separating the northeastern 
 portion of the Penobscot drainage-basin from the sources of 
 the St. Croix and Machias Kivers. South of the Rangeley 
 Lakes, also, where Ellis River joins the Androscoggin, it is 
 
KAMES. 343 
 
 Only a barrier of two or three hundred feet which causes the 
 present deflection of the river to the east, through Lewiston 
 to Brunswick. The great bend made by the Merrimack 
 Kiver at Lowell, Mass., is also caused by a glacial deposit to 
 the south of only fifty or sixty feet in height. 
 
 It is easy to see that, during the period of most rapid 
 retreat, when the waters of the wasting ice-sheet over New 
 England were seeking their ultimate channels, the lower 
 portion of the ice itself was an important element in deter- 
 mining the minor deflections in these lines of drainage. An 
 ice-barrier of a few hundred feet in the Penobscot, between 
 Passadumkeag and Mattawamkeag, would force the drainage 
 of the Aroostook region into the valley of the Machias, and, 
 in the predominance of the mountains from which the west- 
 em branches of the Penobscot River descend, we have a 
 cause favoring such an extension of the ice as would produce 
 the results indicated. In the case of the Merrimack River, 
 the fact that, from Lowell to Newburyport, it flows in a 
 northerly direction would also furnish a probable ice-barrier 
 which for a time would drive the drainage of this basin di- 
 rectly southward from Lowell and Lawrence toward Boston. 
 
 It is not necessary to go into all the details concerning 
 the intricate network of kames which mark the lines of 
 drainage over New England, when ice-barriers to so great 
 an extent directed the flow of the glacial torrents. The facts 
 are impressive. Individual kames can be traced for long dis- 
 tances, sometimes a hundred miles or more. The main lines 
 in New England are shown on the accompanying map, be- 
 ginning on the eastern side of Maine.* 
 
 A few points merit particular attention. The Connecti- 
 cut River Valley, from its sources to the Massachusetts line, 
 contains the remnants of what seems to be a pretty continu- 
 ous kame, but which has been largely eroded, and in many 
 cases covered up by subsequent deposits of river-silt. Almost 
 
 * See also " Kames and Moraines of New England " in " Proceedings of the 
 Boston Society of Natural History," vol. xx, p. 211 et seg. 
 
344 
 
 THE IGE AGE IN NORTE AMERICA. 
 
 everywhere we find illustrations in the partial burying of 
 kames by such river-silt that the deposition was previous 
 
 BCAt-E OF MILES 
 
 :.->Utiera j- Uj.. JSngr'a, S. V. 
 
 Fig. 104.— The kames of Maine and southeaBtem New Hampehire. The eytension from 
 New Hampshire can be seen in Pia. lOL (Stone.) 
 
 to and independent of the present streams. For example, 
 the Merrimack, between Lowell and its mouth, is crossed at 
 right angles by two or three lines of kames, which descend 
 into the valley from one side and come out upon the hills on 
 the other. "While crossing the valley these are partially, 
 
KAMES. 345 
 
 and in some places completely, buried beneath the river-silt 
 ■which forms the present flood-plain. In one case, a few 
 miles below Lowell, the end of this ridge, completely cov- 
 ered with river-silt, may be seen where the river has cut 
 across the old barrier. Professor Charles Hitchcock gives 
 a similar section of a buried kame in Hanover, N. H., though 
 
 • T.,,,™ „f-pi„„j Tj . . '''S S S TTanover Af. Coll. Delta of 
 
 jj Terrace of BloodyBr., ^ r< ci.% ^ "A commoD. fenn. Mink Br 
 
 SNoTO.chy.lUge, 5=5. S. |«^PS Mft 545- fioo." 564. 
 
 ■ .V^«»,>!!ss^ _ 350 ft. 
 
 above 
 sesu 
 Fig. 105.— Section across the Connecticnt Valley, from Norwich, Vermont, to Hanover, New 
 Hampshire, distance three miles. The kame is nearly covered by later river silt 
 (Upham.) 
 
 in this case it is parallel with the river, and not, as in the 
 other, at right angles to it.* 
 
 Inasmuch as the interpretation of the facts in the valley 
 of the Connecticut is open to some question, and as the de- 
 cision with respect to them will have an important bearing 
 on our whole conception of the closing scenes of the Glacial 
 period, it will be worth while to consider them more fully. 
 
 Mr. Upham, in his survey of the Connecticut Yalley,f 
 discovered what he considered to be a line of kames extend- 
 ing throughout nearly the whole length of the valley, though 
 it had been much eroded in places, and in others was partially 
 or completely buried by river-silt ; but of the character of the 
 deposit as a true kame he felt quite confident — that is, he con- 
 sidered that the line of gravel ridges which he found winding 
 from side to side down this valley were deposited as the ice 
 retreated, after the manner we have described in channels 
 and tunnels formed near the front. In this view these ridges 
 in age are intermediate between the till and the regular river 
 
 * " Proceedings of the American Association for the Advancement of Sci- 
 ence," vol. xxxi, p. 328 ; also Upham, in " Geology of New Hampshire," vol. iii. 
 
 + See "Geology of New Hampshire," vol. iii, pp. 3-177; also, "American 
 Journal of Science," vol. cxiv, 1 S'??, p. 459. 
 
346 THE ICE AOE IN NORTH AMERICA. 
 
 terraces — being newer than the till and older than the ter- 
 races. 
 
 On going over the ground in 1881 with Mr. Upham's 
 notes in his hands, Professor Dana concluded that what Mr. 
 Upham had called kames were in reality a portion of the 
 regular terrace formation. In Professor Dana's view, the 
 reputed kames are merely the coarser part of the terrace 
 material accumulated in excessive amoimt in the larger val- 
 ley wherever tributary streams brought into it their heavier 
 burdens from the higher land. On this theory, the height 
 of the floods in numerous localities must have been between 
 two hundred and three hundred feet above low water in the 
 river ; for in various places these deposits are at that height 
 above the river. But upon the supposition that they are 
 
 SegRsatedTetns 
 ialiuKer pottioBa 
 
 37S ft. above sea. 
 
 Fig. 106. — Section east from Ledyard Bridge, Hanover, New Hampehire, showing segre- 
 
 fated veins in the lower portion. Lengtb, about seven hnndred feet. Height of 
 ame above the river, one hundred and forty feet. (Upham.) 
 
 kames, deposited when the ice itself formed barriers to keep 
 the streams in various abnormal positions, the glacial floods 
 would not need to be more than from one hundred to one 
 hundred and fifty feet in height, since that is all that is 
 required for the deposition of the highest river-silt which 
 occurs. 
 
 It must be confessed that Professor Dana's estimates of 
 the size of the Connecticut Kiver floods at that time are 
 somewhat startling, even with all the changes of level for 
 which he provides in his theory.* For, after reducing, by 
 reason of the Ohamplain depression, the gradient of the 
 stream during the close of the Ice period by one third, the 
 
 * "American Journal of Science," vol. cxxiii, 1882, p. 198. 
 
KAMES. 347 
 
 slope of the surface of the Connecticut would still have been 
 more than one foot per mile. This, in a torrent 2,500 feet 
 wide, with a depth of 140 feet, would produce a current of 
 eight miles per hour on the surface and of six miles on the 
 bottom. With this size of the flood, the rate of discharge 
 would be about four hundred cubic miles of water per an- 
 num ; whereas, at the present time, the total discharge of a 
 year is only about five cubic miles. To cause this enormous 
 rate. Professor Dana supposes that, for a short period, the 
 Connecticut glacier melted at the rate of more than a cubic 
 mile per day. As he estimates the area of this drainage-basin 
 to be about 8,500 square miles, this would imply that at times 
 as much as eight inches per day melted from this surface. 
 This rapid rate of removal' in summer is not, however, sup- 
 posed to continue for a long period — probably less than five 
 years. Professor Dana supposes that, at that time, the long 
 tunnels worn in the glacier by the Connecticut and its tribu- 
 taries, when they existed as subglacial streams, had become 
 open channels in the ice. 
 
 Later and fuller investigations of Professor Emerson, 
 give a different interpretation to many of the facts in the 
 Connecticut Valley. It would now appear that the ice dis- 
 appeared from the high lands on either side before it did in 
 the valley, so that there was a series of marginal lakes at 
 successively lower levels leaving accumulations of gravel, 
 and these were traversed occasionally by kame-like ridges. 
 This conforms to what was evidently the course of events in 
 the Champlain Valley parallel to it. There high-level gravel 
 deposits which were at first supposed to be indications of a 
 general depression of land, are explainable on the theory of 
 marginal glacial lakes. 
 
 The shore lines of such marginal lakes are clearly marked 
 at Bakersfield, Franklin County, Vermont, and southward 
 in the valleys of the Lamoile and Winooski rivers. The 
 bowlder channel in Chazy, N. Y., described above, p. 320,. 
 marks as already said a water weir between the decaying 
 ice-sheet and the Adirondack Mountains. 
 
348 
 
 THE ICE AGE IN NORTE AMERICA. 
 
 The levelly stratified plains of sand and gravel which 
 spread out around the southern end of the kame systems, and 
 which to a greater or less extent border their margin through- 
 out their entire length, should not be passed without notice, 
 
 Fig. 107.— Buried kame near Strondsburg, Pennsylvania. (Lewie and Wright.) 
 
 since they in a remarkable degree confirm our general theory 
 concerning the origin of kames. As has been said, the 
 kames mark the great lines of drainage which poured over 
 the southern margin of the glaciated area during its later 
 stages when the ice itself furnished numerous and important 
 barriers to direct the torrents, and when the earthy material 
 in and on the ice was readily at hand to be swept along by 
 these temporary streams. The pebbles, sand, and gravel 
 lodged by the way in the ice-channels, and on the surface, 
 furnished the material from which the kames were to be 
 formed. Wherever these streams came out of their confine- 
 ment and flowed over a level coontry, they deposited vast 
 deltas of sand and gravel, analogous to those that are now 
 being deposited at the mouths of all large rivers. One of the 
 most remarkable of these kame-deltas is that in Cherryfield 
 and Deblois, near the eastern coast of Maine. This sandy 
 plain, many miles in extent, is not an ocean deposit, but can 
 be readily connected with the streams which deposited to the 
 north of it one of the largest belt of kames in the State, and 
 whose course can be traced for nearly one hundred miles 
 toward Mount Katahdin. Down the line of the kame there 
 poured, between icy walls, during the closing stages of the 
 Glacial period, a vast but fitful silt-laden stream of water, 
 which, as it emerged from its more constrained limits within 
 the ice-sheet, was slackened in its movement and rapidly de- 
 
KAMES. 349 
 
 posited the strata of sand and grayel forming the above- 
 mentioned delta-plain.* 
 
 This is but a type of innumerable other places. As the 
 ice receded and the mouth of the kame-streams retreated to 
 the north, the line of these deposits receded, and deltas were 
 pushed out now upon one side and now upon another of the 
 central kame. Often one can see these aprons of stratified 
 deposits stretching out from the base of the kame into a 
 swamp, the stream at that point not having been stationary 
 long enough to allow the whole depression into which it was 
 flowing to become iilled with silt. Nearly all of the exten- 
 sive gravel deposits in New England are thus related to some 
 kame system, so that, when once their origin became under- 
 stood, they were the means of assisting in the discovery of 
 the kames themselves. An interesting illustration of this 
 occurred in the case of the kames running through the 
 Eangeley Lakes from north to south, and extending to the 
 Androscoggin Eiver and beyond, south of Andover, Me. 
 From the extent of the gravel plains to the north of Port- 
 land, Mr. Upham had surmised that a kame-stream must 
 have come down from the north to account for the deposit. 
 My brother, Kev. W. E. C. Wright, was soon after requested 
 to look for such a kame in the course of a pleasure-trip he 
 was about to make to these lakes. This he did, and the re- 
 sult was that, what Mr. Upham had seen with the mind's 
 eye, the summer tourist had no difficulty in finding in reality. 
 The kame can be traced up the stream not only to the lakes, 
 but through and across them — their backs appearing occa- 
 sionally above the water, and their line forming a shoal from 
 one side to the other 
 
 These aprons of over-wash gravel, marking the deltas of 
 the kame-streams during the close of the lee age, also char- 
 acterize the whole glacial border to a greater or less extent. 
 The entire south side of Cape Cod and of Long Island f pre- 
 
 * See :i.ap, p. 344. 
 
 f See " The Geological Formation of Long Island, New Tork, with a Descrip- 
 tion of its Old Water-Courses," by John Bryson, 1886. 
 
350 THE lOE AGE IN NORTH AMERICA. 
 
 sents a bordering plain of sand and gravel, deposited, in the 
 manner above described, about the base of the great terminal 
 moraine, and decreasing in height as the distance increases 
 from the base to the south. Similar deposits characterize 
 the southern flanks of the kettle-moraine of Wisconsin and 
 its extensions both east and west. Several such are crossed 
 upon the railroad from Elkhorn to Eagle, in Walworth county, 
 Wis., wh6re the hills of the moraines are to the north, and 
 much low, swampy land lies to the south and east. It is evi- 
 dent that the ice remained here just long enough for the cur- 
 rents of water which swept down from the moraine to fill the 
 depression with sand and gravel from its base down to the 
 line of the railroad, whereupon the retreat of the ice-front 
 allowed the course of the drainage to change, and to build 
 up deltas at some other point. 
 
 The discussion of kames is not complete without directing 
 attention to the fact that they do not by any means always 
 occupy a continuous slope from the highlands to the glacial 
 margin ; and this has an important bearing upon the ques- 
 tion of the mode of their formation, and their connection 
 with ice-barriers and with ice-channels. Frequently, when 
 following a kame down a gentle incline or over a level plain, 
 it will be found that, on coming to a transverse valley one 
 hundred and fifty or two hundred feet in depth, and perhaps 
 more, the kame is not interrupted, but it descends into the 
 valley on one side, and ascends on the other to the level plain 
 beyond. This feature of the kames across the Merrimack 
 River above Lawrence, Mass., has already been referred to. 
 and it early attracted my attention, and was fully described 
 in one of my first papers on the subject.* 
 
 Another interesting illustration of this phenomenon, and 
 one which reveals the ingenuity of the investigator, is re- 
 lated by Professor Stone respecting the kame which crosses 
 Schoodic Lake in eastern Maine. He had followed the kame 
 
 * See "Some Remarkable Gravel Ridges" ; also, " The Kames and Moraines 
 of New England " ; also, map p. 338. 
 
KAME8. 351 
 
 to the north end of the lake, and had also learned of its ex- 
 istence on the south end. Wishing to ascertain whether the 
 kame was continuous to the other end, he inquired of the 
 lumbermen who are in the habit of " warping " rafts of logs 
 through the lake whether there was not a line of shoal water 
 through it. But none of them had become aware of any such 
 shallow hne.* On asking them, however, if the anchorage 
 was equally good at all places in the lake, they at once re- 
 plied that it was not ; that at certain places the bottom was 
 gravelly, and the anchors would not hold. Upon asking what 
 they did in such an event, they replied that all they had to 
 do was to take the anchor to one side or the other, when usu- 
 ally there was no difficulty in finding a good bottom. The 
 explanation, to Professor Stone's mind, of this state of things 
 was, that the gravelly places of poor anchorage were along 
 the line of the kame, and, by asking the lumbermen to mark 
 upon the map the places where the anchor was in the habit 
 of dragging, and which they were compelled to avoid, he 
 was able to trace the kame from one end of the lake to the 
 other. 
 
 Instances like this, of the indifference of the kames to 
 the minor irregularities of the slopes of the valleys in which 
 they are situated, are frequent. One worthy of special note 
 is found in the valley extending from "Wakefield, Carroll 
 county, N. H., northward to Ossipee Lake. In this case 
 two kame systems meet each other in the depression of the 
 lake, having slowly descended for many miles, the one from 
 the north and the other from the south. The explanation 
 is that the outlet of Ossipee Lake is to the east, joining the 
 Saco Kiver at Cornish. Evidently this drainage-channel 
 through the ice was opened while the ice still filled the 
 southern part of Carroll county as far south as the head- 
 
 * The process of warping rafts is as follows : An anchor is taken out some 
 distance ahead of the raft and dropped upon the bottom ; whereupon a wind- 
 lass upon the raft connected with a rope that is fastened to the anchor is turned, 
 and the raft is thus slowly drawn to the point over which the anchor is caught, 
 when the anchor is raised and again taken forward, to have the process repeated. 
 
352 THE ICE AGE IN NORTH AMERICA. 
 
 waters of the Piscataqua River. Thus there was, along a 
 certain margin of the ice, a backward drainage of twenty 
 miles or more, which offers a ready explanation for this 
 seeming anomaly in the relation of the kame to the general 
 slope of the valley down which the ice had moved. 
 
 Several other instances, equally marked, described by 
 Professor Lewis,* exist in the eastern counties of Pennsyl- 
 vania. In these eases a great amount of glacial debris had 
 been deposited upon the ice, a little back from its front, on 
 the west side of the Delaware River, both above and below 
 the Water-Gap. South of the Water-Gap these deposits are 
 several hundred feet higher than the Delaware River, and 
 lie between it and Kittatinny Mountain. When the Delar 
 ware had opened its own channel back to the present site of 
 Portland, just below the Water-Gap, a line of backward 
 drainage was established from the higher land on the south- 
 west toward the northeast. This line is now marked for a 
 number of miles by a very well-developed system of kames. 
 
 A similar line of kames descends the valley of Jacobns 
 Creek along the line of drainage to the Delaware River^ 
 sloping backward from the glacial margin near Johnson- 
 ville toward Stroudsburg. Down this backward slope, for 
 a distance of five miles or more, the kames are very con- 
 spicuous. 
 
 The gravel-ridges occurring in the southern or upper end 
 of the numerous transverse valleys containing the Finger 
 Lakes of central New York seem to be similar instances of 
 kames formed by backward drainage. The course of events 
 there seems to have been as follows : After the ice melted 
 back to the water-shed between the Mohawk and the Sus- 
 quehanna River, a large amount of water-worn material 
 accumulated upon and about the margin before the great 
 line of drainage through the Hudson and Mohawk Rivers 
 opened. When, finally, the streams of this region were re- 
 
 * "Marginal Kames," in "Proceedings of the Society of Natural Sdences," 
 Philadelphia, June 2, 1885, pp. 157-173. 
 
KAMES. 
 
 353 
 
 Sne of the 
 Lake re- 
 
 stored to their natural course 
 Mohawk was resumed, these 
 gion would be naturally fo 
 
 Westward from New YoJ%4lHH|^Rbns are not favor- 
 able for the fomiation of this clilfetoMpaeial deposits. Still, 
 there are numerous short series of'^raies in Ohio at the low 
 place in the water-shed between the lake and the tributaries 
 to the Ohio River. Through these the glacial torrents poured 
 over into the southern streams during all that period when 
 the outlet through the Wabash was closed up and the dam 
 across the Mohawk Yalley was at its height. Karnes are 
 abundant in JmHuit county, between. Ravenna and Akron, 
 
 and south 
 dina cou: 
 Occi 
 in 
 
 monv 
 of 
 
 fhe neighborhood of Seville, in Me- 
 
 e ridges are reported farther west, as 
 
 Minn.* But, according to the testi- 
 
 whose experience is wider than that 
 
 these investigations, "prolonged kames, 
 
 those of Sweden and Scotland, and with 
 
 in Maine, New Hampshire, and Massachu- 
 
 been found." f 
 
 A summary of the last three chapters may be helpful here : 
 The extreme length of preglacial as compared with post- 
 glacial time is evident from the enormous extent of pregla- 
 cial erosion. Outside the glaciated region all the rivers oc- 
 cupy deeply eroded valleys, showing the great length of the 
 time through which eroding agencies have been at work. 
 Thd^fc^^lacial gorge of Niagara is but seven miles long, 
 I whereas^he preglacial gorge of Ohio is both wider and 
 * deeper Wian that, and is more than a thousand miles in 
 length. 
 -7. It j8 easy to see that all the northerly-flowing streams of 
 f ©J^afeRal drainage would be dammed up by ice during the 
 
 *^reological and Natural History Survey of Minnesota," vol. i of the final 
 p. 646. 
 'bid., " Ninth Annual Report," p. 290. 
 
354 , THE IQM. %fiE IN NORTH AMERICA. 
 
 greater parW| tb^ffe&QJpi'period. Of this as a reality there 
 is abundant ©i^dgMiBi ,<A^]FJ:^e streams which rise within 
 the glaciated re^a >ft§^ld\t-^^ffithward were compelled to 
 carry away not o^- tlt^fcinllal precipitation, but, during 
 the closing stages oi^M, period, the waters of the accumu- 
 lated precipitation of MjHy thousands of years. If the an- 
 nual spring freshets of these streams are oftentimes terrific, 
 what must have been the spring freshets in the Glacial period 
 itself! 
 
 Into the Mississippi also were poured the surplus waters 
 which now flow down the St. Lawrence, and into Hudson 
 Bay. Lake Erie emptied its waters thMMffftthe Wabash 
 River, and Lake Michigan down ^|*';Ii 
 great region drained by the Red a^»6;tJhpr 
 toba and British Columbia had thei»«j)nti£|''' 
 Traverse and Big Stone Lake, into^te*,^? 
 thence into the lower Mississippi. Th^^aei^ 
 ciated region are the direct results of t|^ 
 and can be studied on every stream within i| 
 
 Besides the glacial terraces of our presSnt. 9tiSEEin:\pv^e 
 have, in the so-called " kame systems," still fTmher^ddence 
 of the existence of temporary lines of draina^ determined 
 by ice-barriers. New England is gridironed by a system of 
 gravel-ridges deposited by glacial streams which were^ to a 
 great extent, independent of the minor features in the pres- 
 ent topography. In these and in the terminal moraines we 
 study the skeleton of the continental ice-sheet as intelli- 
 gently as the anatomist can study the skeleton of a diwr , 
 sected animal. k ' ; . #, t i* 
 
 '•'*, «^ J* *. ^ 
 
CHAPTER XV. 
 
 GLAOIAI. DAMS, LAKES, AND WATEEFALLS. 
 
 No single cause has done more to diversify the surface of 
 the country, to add to the attractiveness of the scenery, and 
 to furnish the key by which the conditions of the Ice age 
 can be reproduced to the mind's eye, than glacial dams. To 
 them we owe the present existence of nearly all the water- 
 falls in North America, as well as nearly all the lakes, while 
 the shore-lines and other marks of temporary bodies of water 
 produced by ice-barriers are of the most instructive character. 
 
 In the chapter upon "Glacial Erosion and Transportation" 
 we have already spoken at some length of rock-basins which 
 have been formed by glacial action. In the case of the so- 
 called cirques there described, there can be no question that 
 they have been produced by ice-action, the rocks being worn 
 deepest where the ice impinged upon them most directly and 
 for the longest period of time, leaving at the front a rocky 
 rim much higher than the bottom of the cirque. To what 
 extent the fiords, and the lakes which are some distance from 
 mountain declivities and have rock-rimmed basins, owe their 
 origin to the same cause, is an unsettled question ; and still 
 greater doubt appertains to such basins as are occupied by 
 the great lakes of the United States and British America. 
 Professor Newberry, whose opportunities for investigation 
 have been most ample, would attribute these lake-basins 
 ■largely to glacial erosion.* 
 
 * " Notes on the Surface Geology of the Basin of the Great Lakes," " Bos- 
 ton Society of Natural History. 1862 " ; " Geological Surrey of Ohio, Report of 
 
356 TEE WE AGE IN NORTH AMERICA. 
 
 It is fair to Professor Newberry, however, to state that 
 he never took extreme grounds upon this point, but that his 
 fullest statement of the theory, written for the second vol- 
 ume of his " Report of the Geological Survey of Ohio," was 
 well matured, and gave weight to all the agencies which 
 combined with ice-action to produce these basins. The facts 
 which have to be borne in mind with reference to the Great 
 Lakes are briefly these : 1. Lakes Ontario, Erie, Huron, and 
 Michigan, being surrounded by sedimentary rocks whose 
 strata at the present time lie nearly horizontal, evidently 
 occupy valleys of erosion. The western end of Lake Supe- 
 rior, however, occupies a synclinal trough, and is doubtless 
 partly due to an early warping of the earth's crust. 2. The 
 bottoms of all these lakes, except Erie, are lower than the 
 present sea-level, the depression in the case of Superior 
 being 375 feet ; Michigan, 286 ; Huron, 127 ; Ontario, 507. 
 If, then, these lakes occupy valleys of erosion, it is an inter- 
 esting question to determine how any erosive agency could 
 have operated to such a depth below sea-level. 
 
 Professor Newberry's theory is that, previous to the Gla- 
 cial period, the region to the south and southwest of Hudson 
 Bay was considerably elevated above its present position, 
 and that from early ages the lines of drainage had been 
 established in pretty much the same general course as at 
 present, forming valleys of considerable extent where now 
 the lake-basins exist ; that, when the Ice age came on, the 
 country to the north was still at a higher elevation than 
 now, and as the local glaciers increased, they occupied, en- 
 larged, and in some cases deepened, these old river-valleys, 
 both by direct action in eroding the rocky basin and by 
 the deposition of great quantities of glacial detritus. But 
 his own statement of the theory is so perspicuous and 
 
 Progress for 1869 " ; " The Surface Geology of the Basin of the Great Lakes 
 and the Valley of the Mississippi," " Lyceum of Natural History Society, New' 
 York, 1869"; "The Surface Geology of Ohio," "Report of Geological Survey 
 of Ohio," vol. ii, 1874 ; " The Geological History of New York Island and Har- 
 bor," "Popular Science Jlonthly," 1878. 
 
GLACIAL DAMS, LAKES, AND WATERFALLS. 357 
 
 condensed that we can do no better than reproduce the most 
 of it : 
 
 Previous to the Glacial period the elevation of this por- 
 tion of the coutinent was considerably greater than now, and 
 it was drained by a river system which- flowed at a much lower 
 level than at present. At that time our chain of lakes — 
 Ontario, Erie, and Huron — apparently formed portions of the 
 valley of a river which subsequently became the St.- Lawrence, 
 but which then flowed between the Adirondacks and Appa- 
 lachians, in the line of the deeply buried channel of the Mo- 
 hawk, passing through the trough of the Hudson and empty- 
 ing into the ocean, eighty miles southeast of New York. Lake 
 Michigan was apparently then a part of a river-course which 
 drained Lake Superior and emptied into the Mississippi, the 
 Straits of Mackinaw being not yet opened. 
 
 With the approach of the cold period, local glaciers formed 
 on the Laurentian Mountains, and, as they increased in size, 
 gradually crept down on to and began to excavate the plateau 
 which bordered them on the west and south. The excavation 
 of our lake-basins was begun, and perhaps in large part effect- 
 ed, in this epoch. 
 
 As the cold increased and reached its maximum degree, a 
 great ice-sheet was formed by the enormously increased and 
 partially coalescing local glaciers of the former epoch. This 
 many-lobed ice-sheet, or compound glacier, moved radiatingly 
 from the south, southwest, and western slopes of the Canadian 
 highlands, its Ohio lobe reaching as fa,r south as Cincinnati. 
 The effect of this glacier upon Lake Erie and Lake Ontario 
 would be to broaden their basins by impinging against and 
 grinding away with inconceivable power their southern mar- 
 gins. To the action of this agent we must ascribe the jjeculiar 
 outline of the profile sections drawn from the Laurentian 
 Hills across the basin of Lake Ontario to the Alleghauies, and 
 across that of Lake Erie to the highlands of Ohio, viz., a long, 
 gradual slope from the north to the bottom of the depression, 
 and then an abrupt ascent over the massive and immovable 
 obstacle against which the ice was banked, until, by the vift a 
 tergo, it overtopped the barrier. In ITew York that barrier 
 
358 THE ICE AQE IN FORTH AMERICA. 
 
 was a shoulder of the Alleghanies, too high and too rugged to 
 be buried under a continuous ice-sheet; but its whole front 
 was worn away for a hundred miles or more, and it was deeply 
 creased where now we see the peculiarly elongated lakes of 
 New York, and cut through in certain gaps, to the valley of 
 the Delaware. In Ohio the erosion was easier and carried far- 
 ther south. The barrier was also lower, and was finally over- 
 topped by one great lobe of ice, which flowed on to the south 
 and west until its edge reached the Ohio Kiver. . . . 
 
 With the amelioration of the climate the wide-spread ice- 
 sheets of the period of intensest cold became again local gla- 
 ciers, which completed the already begun work of cutting out 
 the lake-basins. At first, the glacier which had before flowed 
 over the water-shed in Ohio was so far reduced as to be unable 
 to overtop its summit ; but, deflected by it, it flowed along its 
 base, spending its energies in cutting the shallow basin in 
 which Lake Erie now lies. 
 
 A further elevation of temperature curtailed the glacier 
 still more, and Lake Erie became a water-basin, while local 
 glaciers left from the ice-sheet excavated the basins of Lake 
 Michigan, Lake Huron, and Lake Ontario. The latter lake 
 wias apparently formed by the same glacier that made the Erie 
 basin, but when much abbreviated. It flowed from the Lau- 
 rentian Hills and the north slope of the Adirondacks, and was 
 deflected by the highlands south of the lake-basin, so that its 
 motion was nearly westward. This chapter in the history of 
 our lakes was apparently a long one, for Lake Superior, Lake 
 Michigan, Lake Huron, and Lake Ontario are all of great 
 depth. 
 
 The melting of the glaciers was accompanied, perhaps 
 ' occasioned, by a sinking of the continent, which progressed 
 until the waters of the Atlantic flowed up the valley of the St. 
 Lawrence to Kingston, and up the Ottawa to Arnprior (Daw- 
 son). The valleys of the St. Lawrence and the Hudson were 
 connected by way of Lake Champlain, and thus the highlands 
 of New England were left as an island. It is also possible that 
 the sea-water penetrated to the lake-basin through the valley 
 of the Mohawk and through that of the Mississippi, but of 
 this we have no evidence in the presence of marine fossils in 
 
GLACIAL BAMS, LAKES, AND WATERFALLS. 359 
 
 the surface deposits. The great area of excavation in which 
 the lakes lie was probably at this time filled to the brim with 
 ice-cold fresh water; and this, flowing outward through all 
 the channels open to it, may have been sufficient to prevent 
 the entrance of the arctic marine mollusks, of which the re- 
 mains are so abundant in the Ohamplain clays of the St. Law- 
 rence Valley and the Champlain basin.* 
 
 Lakes caused by glacial dams are of two classes : L Those 
 produced by the irregular deposition of moraine material ; 
 2. Those caused by the ice itself during the period of its 
 continuance. The first of these classes may also be profit- 
 ably subdivided into — (1) Those caused by deposits which 
 have closed up old water-courses ; (2) Those caused by de- 
 posits producing complete inclosures of the nature of kettle- 
 holes. 
 
 Making the last class the first subject of consideration, 
 we note that by far the larger number of the small lakes 
 which diversify the glaciated region occupy the basins of 
 kettle-holes. When treating of terminal moraines and 
 kames, kettle-holes were spoken of as one of the prominent 
 features characterizing these deposits, and the origin of the 
 smaller ones at least was said to be due to the melting away 
 of masses of ice which had from time to time been covered 
 by the earthy debris which accumulates near the front and 
 along all the great lines of drainage of extensive glaciers. 
 Protected for a while by this debris from melting, these 
 masses of ice first begin to disappear around the exposed 
 edges of their sides, allowing the sand, gravel, and pebbles 
 to be heaped up about their bases, so that, upon the final 
 disappearance of the ice, an inclosure is left, varying in size, 
 shape, and depth according to the extent of the ice-mass 
 inclosed. Many of these kettle-holes are dry throughout the 
 larger part of the year, since they are above the general 
 level ; and the surrounding material of the rim is so coarse, 
 that, even after long-continued rains, the water remains in 
 
 * " Geology of Ohio," vol. ii, pp. 11-19. 
 
360 THE ICE AGE I^^ NORTH AMERICA. 
 
 them but a short time ; w Idle others, whose bottom is below 
 the general surrounding water-level, or whose rims chance 
 to be of more compact material, retain a small amount of 
 water during the most of the season, or throughout the 
 entire year. In innumerable cases peat has accumulated in 
 the bottoin of these, and filled up a considerable portion of 
 the lower part of the cone-shaped depression. It is thus that 
 nearly all the peat-bogs of New England and the JS^orthwest 
 have originated. In numerous cases the peat forms a rina 
 about the edge at the water-level, while in the deeper por- 
 tion the surface of the clear water looks up from the shad- 
 ows, or reflects the sunshine like the pupil of a gigantic eye. 
 In respect to these glacial lakes partially surrounded by 
 accumulations of peat, one almost uniformly finds local tra- 
 ditions that they are without bottom, or at least that no one 
 has been able to find it. The fact is, however, that they ai"e 
 none of them of great depth ; but the soft ooze of muck and 
 mud which accumulates at the bottom renders sounding 
 impracticable, and thus originates the illusion of unfathom- 
 able depths. 
 
 The lakes and bogs of Ireland present familiar examples 
 of this class of glacial inclosures ; while in this country one 
 can not easily run amiss of them, either in New England or 
 the Northwest. The southeastern portion of Massachusetts 
 abounds in them in special degree. As before remarked, 
 Plymouth county is little less than a ganglion of such gla- 
 cial lakes with their inclosing deposits — Plymouth township 
 alone being reputed to have three hundred and sixty. They 
 appear all along the line of the terminal moraine, often cap- 
 ping its very summit in the western portion of Long Island, 
 even within the limits of the city of Brooklyn. 
 
 As shown in a previous chapter,* the Elizabeth Islands 
 consist of a network of deposits surrounding such depres- 
 sions ; but in this case, as frequently elsewhere, the rims are 
 of such coarse material that most of the depressions are dry. 
 
 * See p. 205. 
 
GLACIAL BAMS, LAKES, AND WATERFALLS. 361 
 
 All the lines of the kaiue-deposits in Maine, ISfew Hamp- 
 shire, and Massachusetts are marked by the frequent occur- 
 rence of lakes and drj depressions of this description. 
 " Tight Pond," the name of one in the vicinity of Conway, 
 N. H., is suggestive of its character. The resemblance so 
 often noted by tourists between the scenery of Michigan 
 and that of large portions of Ireland is produced by the pre- 
 ponderance in both regions of this class of lakelets. The 
 innumerable lakes of Wisconsin and Minnesota had a similar 
 origin, and are limited chiefly to the tortuous line of the 
 great Kettle Moraine, heretofore described as being so 
 marked a feature in the topography of the country between 
 Lake Michigan and Dakota. 
 
 It was a k-ng time before the true origin of these lake- 
 lets in the Northwest was suspected. But no sooner was 
 Mr. Upham set to survey the field in Minnesota, than, with 
 his knowledge of the glacial phenomena of New England, 
 he detected their character, and at once adopted a pi'ovisional 
 hypothesis by which he successfully and economically direct- 
 ed his future glacial investigations in the State. The lake- 
 lets and dry depressions above Minneapolis, including even 
 Lake Minnetonka itself, he perceived to be kettle-holes, such 
 as characterize the terminal moraine on the southern shore 
 of New England, and at once inferred that the moraine in 
 that State would be found running along the curved lines 
 formed by these lakelets, as laid down upon the maps by the 
 topographical surveyors. There was a belt of such lakelets 
 running a little west of north from Minneapolis, between 
 the valley of the upper Mississippi and that occupied by the 
 Minnesota and the southern part of the Eed River of the 
 North. In the vicinity of Minneapolis there was also a 
 peculiar enlargement of this area of lakelets, whence it ex- 
 tended into northern • Iowa, but, for a width of sixty or 
 seventy miles, and a length of two hundred and fifty or 
 three hundred miles up and do^vll the Minnesota Yalley, 
 there was a striking absence of lakes upon the maps. They 
 reappeared again, however, to the west, in a line nearly par- 
 
362 THE ICE AQE IN NORTH AMERICA. 
 
 allel with the first one described, and extended through the 
 Coteau des Prairies of eastern Dakota. A single season's 
 work was sufficient amply to verify Mr. Upham's hypothe- 
 sis, and all subsequent inyestigation has confirmed it, prov- 
 ing that there was an independent movement of ice down 
 the Minnesota VaUey, pushing its lobate front far into the 
 State of Iowa, and some distance beyond the part reached 
 at that time by the general mass on either side. About 
 this lobate margin a vast moraine was built up, whose 
 irregular deposits formed the inclosures containing the lake- 
 lets of that region. Over the intervening area, for a width 
 of seventy miles, there is little left but the ground mo- 
 raine, which is uniform in character, and from which the 
 ice melted so rapidly that there was no chance for the for- 
 mation of lakelets such as characterized the margin where 
 the ice-front remained during the larger part of the 
 period. 
 
 Another class of glacial lakes is due to dams of glacial 
 debris such as were spoken of in a preceding chapter. The 
 lakes of this class are not so numerous as the former, but pre- 
 sent a greater variety of problems for investigation. To 
 appreciate this part of the glacier's work, we must bring 
 again to mind the extent to which erosion had proceeded 
 before the Glacial period began. As already detailed, the 
 vast extent of preglacial erosion is apparent at once upon 
 entering the u'nglaciated region upon the western flanks of 
 the Alleghany Mountains, where all the rivers occupy nar- 
 row troughs of erosion, hundreds of feet deep, and extending 
 to the very sources of the streams. There are, over that un- 
 glaciated region, few if any waterfalls, simply because the 
 recession of the cataracts which once existed has in most 
 cases proceeded so far that the streams have completed their 
 work, and have already cut their channels through to their 
 extreme limit. The State of Ohio is a portion of the Appar 
 lachian uplift, and its surface, for the most part, is more than 
 a thousand feet above the sea. The southeastern part of 
 the State is unglaciated, and is characterized by the freedom 
 
&LAOIAL DAMS, LAKES, AND WATERFALLS. 363 
 
 from waterfalls, and that depth and extent of the eroded 
 valleys, which would naturally result from the prolonged 
 continuance of water-action. On the contrary, the glaciated 
 portion of the State presents a surface in the main remark- 
 ably free from the effects of prolonged water-erosion. The 
 northern and western portions of the State belong practically 
 to the great prairie region of the interior. 
 
 None know just where the old outlet to Lake Winiiepe- 
 saukee in New Hampshire is ; but, from the nature of the 
 situation and the analogies of the case, there can be no 
 doubt that it, together with the most of the larger lakes of 
 New England, is held in place by deposits of glacial material 
 filling up an old outlet. Doubtless, with comparatively little 
 labor, trenches might be dug which should, when not below 
 the ocean, drain them all to the bottom. There can be no 
 doubt, also, that Lake Champlain and Lake George are held 
 in their elevated positions by similar glacial dams, and such 
 is certainly the case with many of the numerous lakes which 
 dot the glaciated region of northern New Jersey. To a 
 similar origin is due the remarkable series of parallel lakes 
 in central New York, having at the present time a common 
 outlet in the Oswego River. Chautauqua Lake, now flowing 
 over a rocky bed past Jamestown into the Alleghany, is one 
 of the most elevated of this class of glacial lakes, being held 
 in place by a vast glacial deposit filling up the mouth of an 
 old outlet into Lake Erie. 
 
 The evidence that Lake Erie is caused by the damming 
 up of the old outlet of the valley by glacial debris, has 
 already been presented, and the importance of this fact will 
 appear when we come to discuss the date of the Glacial 
 period. ' 
 
 But, interesting as are these more permanent dams of the 
 Glacial period, they must yield supremacy to the temporary 
 lakes formed by the ice-barrier itself in its various adjust- 
 ments to the topography of the country. Travelers in the 
 Griudelwald Alps have their attention frequently directed 
 to the diminutive specimens of such lakes still existing 
 
364 TEE ICE AGE IN NORTH AMERICA. 
 
 there. The following accurate and interesting account of 
 them is from the pen of Professor William M. Davis : * 
 
 Glacial lakes are now of little importance ; a few occur in 
 the higher mountain-chains, but they are trifling in size, and 
 rank with many other species only as curiosities unless they 
 become of disastrous importance in the valleys below, from the 
 floods that follow a giving way of their barriers. Three sub- 
 species are easily distinguished : First, when the advance of a 
 glacier down a main valley closes the mouth of a lateral ravine ; 
 second, when a glacier fi-om a side valley obstructs the main 
 stream ; third, when the great ice-sheet of early Quaternary 
 times melted away so as to disclose the upper part of a valley 
 sloping gently against it. 
 
 The Merjelen See in Switzerland serves as the type of the 
 first subspecies ; it is held back by the Great Aletsch Glacier 
 in a little valley behind the Eggischhorn, a favorite point of 
 view, from whicli the lake below and the whole stretch of the 
 ice-stream in the main valley can be seen. Sometimes the 
 waters find an outlet through the ice-barrier ; then the slow 
 accumulation of months rushes out in a torrent, flooding the 
 valley of the Massa below, and leaving miniature bergs broken 
 from the glacier stranded on the rocky bottom ; subsequently, 
 another motion of the glacier closes the outlet, and the basin 
 slowly fills again. The highest level of such a lake will be 
 determined either by free escape across the ice, when it will 
 have a variable maximum, or by flow over a pass at the head 
 of its lateral valley. The latter is the case with the Merjelen 
 See, and the level of the pass is marked by a faint terrace and 
 by a change of color on the rocks around the shore, f 
 
 Although rare at present, these lakes have had a consider- 
 able importance in the past. An extinct example was early 
 recognized by Agassiz at the Parallel Roads of Glen Roy, near 
 Ben Nevis, in Scotland ; J these are simply the shore-line 
 
 * " Proceedings of the Boston Society of Natural History," vol. xxi, pp. 
 360, 351. 
 
 •f L. Agassiz, "Etudes sur les Glaciers" (1840), pp. 218, 220. Lyell, 
 " Principles of Geology," vol. i, p. 372 ; " Antiquity of Man," p. 309. 
 
 X Aiassiz, "Geological Society Proceedings," vol. iii, 1842, p. 331; here 
 described as a lateral glacier closing the main valley. 
 
OLAGJaL D.4MS, LAKES, AND WATERFALLS. 365 
 
 terraces of an old ice-barrier lake, the uppermost standing at ' 
 the height of the pass into the next glen, but the cause of the 
 others is not so apparent ; * the glacier which served as a bar- 
 rier has long since disappeared, with all its Scotch com- 
 panions. 
 
 The Mattmark See, representing the second subspecies, is in 
 the Saas valley, becween Monte Kosa and the Ehone, where 
 the AUalin Glacier advances aci-oss the main valley bottom, f 
 It differs from the preceding only in tlie relative position of 
 lake and barrier, and in the lake's level always being deter- 
 mined by flow over the ice or its moraine. The Lac du 
 Combal is in the same way held back by the Glacier de Miage 
 at the southern base of Mont Blanc. Several temporary Swiss 
 lakes of this construction have caused great damage by burst- 
 ing through their barriers. A famous case is that of the 
 Gietroz Glacier in the valley of Bagnes, south of Martigny, in 
 1818. The lake grew to be a mile long, seven hundred feet 
 wide, and two hundred deep. An attempt was made to drain 
 it by cutting through the ice, and about half the water was 
 slowly drawn off in this way ; but then the barrier broke, and 
 the rest of the lake was emptied in half an hour, causing a 
 dreadful flood in the valley below. J In the Tyrol, the Vemagt 
 Glacier has many times caused disastrous floods by its inability 
 to hold up the lake formed behind it.* In the northwestern 
 Himalaya, the upper branches of the Indus are sometimes held 
 back in this way. A noted flood occurred in 1835 ; it advanced 
 twenty-five miles in an hour, and was felt three hundred miles 
 down-stream, destroying all the villages on the lower plain, 
 and strewing the fields with stones, sand, and mud. || 
 
 * Lyell, " Antiquity of Man," p. 300. A good bibliography of this old lake 
 is given by W. Jolly, in " Nature," May 20, 1880, p. 68. 
 
 f Heliotypes of this and the Merjelen See are given in " Glaciers," by Shaler 
 and Davis, Boston, 1881. 
 
 X Lyell, "Principles," vol. i, p. 348. " Bibliothdque Unlverselle de Genfeve," 
 vol. xxi, 1827, p. 227 ; vol. xxii, p. 58 ; vol. xxv, p. 24, etc. 
 
 *Sonklar, "Die Oetzthaler Gebirgsgruppe," Gotha, 186C, p. 154. Stotter, 
 " Die Gletsoher des Vernagtthales in Tirol und ihre Geschichte," Innsbruck, 
 1840, p. 15. 
 
 II H. Strachey, " Royal Geographical Society Journal," vol. xxiii, 1853, p. 56. 
 Compare Drew, Jummoo, and Kashmir. 
 
366 THE ICE AGE IN NORTH AMERICA. 
 
 Mr. J. E. Marr, in recording liis observations upon the 
 Jakobshavn Grlacier, gives the following account of the gla- 
 cial dams connected with it : 
 
 The Jakobshavn Glacier stops up both ends of a valley, 
 running parallel with its course, converting it into a lake, 
 which is separated from the glacier throughout the greater 
 part of its length by a nunatah.* The lower end of another 
 valley considerably to the south of this is stopped by the ice- 
 sheet, and the valley converted into a lake (Tasersiak), which 
 is drained by a river running over the col at the head of the 
 valley into the Strom Fiord, just as in the case of the Merjelen 
 See, only the Greenland lake is much larger than this. A 
 similar lake drains into the North Isortok Fiord, and another 
 into that of Alangordlia. Two similar lakes are formed to the 
 east of Sermilik Fiord, and several small ones to the east of 
 Bjornesund. North of the Frederikshaab Glacier is a valley 
 running north and south, the mouth of which is stopped by 
 the Frederikshaab Glacier, while a tongue of ice flows through 
 a col situated half-way up the valley and bars the valley, one 
 part of the tongue of ice flowing a small distance to the north 
 and another to the south, thus causing the conversion of the 
 valley into two lakes. On the east of the Frederikshaab Gla- 
 cier is the Lake Tasersiak, bounded on the north by the 
 nunatak Kangarsuk, and stopped at its lower end by the Fred- 
 erikshaab Glacier, and having a tongue of the ice-sheet en- 
 tering into it at the upper end. \ 
 
 With these facts concerning existing glacial dams in 
 mind, we are prepared to study the signs of similar obstruc- 
 tions, on a larger scale, which occurred during the progress 
 of the Glacial period. We will first present the facts relat- 
 ing to a supposed obstruction by glacial ice, of the Ohio 
 Kiver at Cincinnati. 
 
 In the summer of 1882, after having the previous year 
 completed, with Professor Lewis, the exploration of the gla- 
 
 * See p. 79. 
 
 t " Geological Magazine " for April, 1887, quoted in the "American Journal 
 of Science," vol. cxxxiv, 1887, p. 313. 
 
QLAOIAL DAMS, LAKES, AND WATERFALLS. 367 
 
 cial boundary through Pennsylvania, I continued the work 
 through the State of Ohio, and traced the line at length to 
 the Ohio River, near Ripley, abonfc sixty miles above Cincin- 
 nati. From this point, for about thirty miles down the river, 
 to the vicinity of New Richmond, the glacial boundary lies 
 upon" the north bank of its trough; till, bowlders, and 
 scratched stones being found on the highlands down to the 
 extreme margin on the north side, but being absent from 
 the corresponding highlands on the Kentucky side. Near 
 Point Pleasant, the birthplace of President Grant, the river 
 makes a long bend to the north, continuing in this direction 
 to Cincinnati, and thence westward to North Bend, the 
 home and burial-place of President William Henry Har- 
 rison ; here it turns south again, thus forming in Kentucky 
 a peninsula, as it were, pointing to the north, and including 
 the territory of Campbell, Kenton, and Boone counties. 
 Upon examining this district it was found that in places in 
 Campbell county, and over the whole northern and western 
 parts of Boone county, there were true glacial deposits on the 
 highest lands — the elevation near Burlington being five hun- 
 dred and fifty feet above low-water mark at Cincinnati. In 
 places, large numbers of bowlders of northern origin were 
 found stranded on the very summit-level of the region — i. e., 
 on the divide, between the short streams running north and 
 those running south, and between the Licking and the Ohio 
 River. They were also found south of this secondary di- 
 vide, seven miles back from the river, and five hundred feet 
 above it (near Florence, Boone county). Several were recog- 
 nized as belonging to a species of red jasper conglomerate, 
 whose outcropping is well marked on the northern shore of 
 Lake Huron and about the outlet of Lake Superior. These 
 bowlders are very beautiful ; and; farther north, where they 
 are more abundant in the fields, are frequently used to adorn 
 the front-yards of residences or even for the construction of 
 public buildings. Some of the citizens of Cleveland, Ohio, 
 have brought large fragments for this purpose from the par- 
 ent ledges. But here, beside a roadway through the Ken- 
 
o«8 
 
 THE ICE AGE IX XORTH AMERICA 
 
 tucky liill>, were large specimens of this same conglomerate 
 (one Ixiwlder lieing nearly three feet in diameter), which had 
 l)een transpcirted bv glacial ice fiiUv six hiriidred niiles from 
 their native bed, and lef ' to tell the storv not only of their 
 OM'U travels, but of other most interesting events connected 
 with the catise wliich trausjiorted them. Thcf-e glacial de- 
 posits sotith of the Ohio are such as to make it certain that 
 the fnmt of the continental glacier itself pushed, at some 
 pciints, seven or eight miles beyond the Ohio River; and it 
 is altogether probable that toi a distance of tifty miles (oi' 
 
 Fig. 10,8 — Contrloinfiah' Ijciuklir 
 
 completely around the eastern, northern, and western sides of 
 the Kentucky peninsula formed by the great bend of the 
 river), the ice came down to the trough of the Ohio, and 
 crossed it so as completely to choke the channel, and form a 
 glacial dam high enough to raise the level of the water five 
 hundred and tifty feet — this being the height of the water- 
 shed to the south. The consequences following are inter- 
 esting to trace. 
 
 The bottoiri of the Ohio River at Cincinnati is 432 feet 
 
370 THE ICE AGE IN NORTH AMERICA. 
 
 above the sea-level. A dam of 568 feet would raise the 
 water in its rear to a height of 1,000 feet above the tide. 
 This would produce a long, narrow lake, of the width of the 
 eroded trough of the Ohio, submerge the site of Pittsburg 
 to a depth of 300 feet, and make slack water up the Monon- 
 gahela nearly to Grafton, W. Va., and up the Alleghany as 
 far as Oil City. All the tributaries of the Ohio would like- 
 wise be filled to this level with the back-water. The length 
 of this slack-water lake in the main valley, to its termination 
 up either the Alleghany or the Monongahela, was not far 
 from one thousand miles. The conditions were also peculiar 
 in this, that all the northern tributaries head within the south- 
 ern margin of the ice-front, which lay at varying distances to 
 the north. Down these northern tributaries there must have 
 poured during the summer months immense torrents of water 
 to strand bowlder-laden icebergs on the summits of such high 
 hills as were lower than the level of the dam. 
 
 The facts leading to this conclusion, together with the 
 theory itself, were first published by me in the " American 
 Journal of Science " for July, 1882.* At the conclusion I 
 added that " it remains to be seen how much light this may 
 shed upon the teiTaces which mark the Ohio and its tribu- 
 taries in western Pennsylvania." Soon after this I received 
 from Professor I. C. White, of Morgantown, W. Va. (whose 
 long experience and careful work upon the Pennsylvania 
 Geological Survey has made his name a synonym for accu- 
 racy of observation and skill in drawing conclusions), a letter 
 stating that the theory of an ancient ice-dam at Cincinnati 
 was the key to unlock what had heretofore been a great puz- 
 zle to the Pennsylvania geologists. Briefly told, the progress 
 of the discovery and discussions concerning it are as follows : 
 
 On all the upper tributaries of the Ohio there are high- 
 level terraces in abundance which the local geologists could 
 with difficulty explain. Upon comparison, however, an im- 
 portant portion of the series was found to have very nearly 
 
 * " American Journal of Science,' vol. cxxyi, pp. 1-14. 
 
GLACIAL DAMS, LAKES, AND WATERFALLS. 371 
 
 the same absolute elevation above the sea-level with that of 
 the assumed top of the glacial dam at Cincinnati. At my 
 request, Professor I. C. White prepared a paper to be read 
 at the meeting of the American Association for the Advance- 
 ment of Science at Minneapolis in the summer of 1883. In 
 this paper the facts concerning the terraces in the valley of 
 the upper Ohio were set forth, together with their bearing 
 upon the existence of the supposed glacial dam. The Min- 
 neapolis meeting was remarkable for the number of distin- 
 guished geologists present who had given special attention to 
 glacial phenomena. Among them was Professor Lesley, who 
 has been for so many years the organizing mind of the Penu- 
 sylvania Geological Survey. When the subject of the Cin- 
 cinnati ice-dam was brought up by the reading of Professor 
 White's paper, Professor Lesley at once gave his adhesion to 
 the theory, and frankly stated that what he had written some 
 years before in explanation of the terraces in western Penn- 
 sylvania was entirely superseded. He had then, in order to 
 account for the terraces, resorted to the hypothesis of a gen- 
 eral subsidence of the region to the extent of several hundred 
 feet. But later he had himself perceived the inadequacy of 
 such an hypothesis, since there were not, as upon this suppo- 
 sition there should be, corresponding terraces upon the east 
 side of the Alleghany Mountains. He had therefore ex- 
 pressed the belief that some local obstruction would be dis- 
 covered in the lower part of the Ohio which would account 
 for the facts. " And now," said he, " Providence has pro- 
 vided one, and Wright's dam will explain it all," and went 
 on to show that the absence of similar terraces on the east 
 side of the mountains was fatal to the theory of a continental 
 subsidence, while it was just what would be expected on the 
 theory of an obstruction of the drainage of the upper Ohio. 
 
 A theory of such wide significance is not, however, to be 
 too hastily accepted, and much attention has since been di- 
 rected toward its verification or disproval. 
 
 In presenting the evidence upon this subject it is well to 
 remark that the study of river terraces brings to light a com- 
 
372 THE ICE AGE IN NORTH AMERICA. 
 
 plex action of forces often difficult to unravel, and peculiarly 
 Kable, in a case like this, to lead one astray. Hence it is 
 probable that a part of the testimony in favor of the Cincin- 
 nati ice-dam, drawn at first from the terraces of the upper 
 Ohio, was irrelevant, since some of the terraces were doubt- 
 less due to the natural progress of river-erosion. For ex- 
 ample, where streams flow down from the flanks of a mount- 
 ain-chain, and have considerable opportunity to deepen their 
 channels, they leave gravel deposits at various levels, and oc- 
 casionally abandon some portion of their old bed to occupy 
 a shorter and deeper cut-off. Upon examination of the 
 Monongahela and its branches, it would seem that several of 
 the terraces at first attributed to the effect of the glacial dam 
 at Cincinnati were formed in the manner thus indicated, or 
 may have been so formed. In this case their remarkable 
 correspondence with the height of the supposed obstruction 
 at Cincinnati is one of those accidental coincidences that are 
 often met with in nature. After eliminating, however, all 
 such eases, there remains a constantly increasing residuum 
 of facts which fairly refuse to be explained, except on the 
 theory supposed. 
 
 Beginning with one of the clearest cases, attention is di- 
 rected to the head-waters of Brush Creek, in Pike county, 
 Ohio. By reference to the accompanying map it will be 
 seen that at the height of the Glacial period the front of the 
 ice rested at the northwest comer of this county. A more 
 accurate study of the details shows that the divide between 
 Paint Creek and Baker's Fork of Brush Creek is formed by 
 the extreme portion of the terminal moraine. Before the 
 Glacial period there was a continuous depression connecting 
 Paint Creek with the valley of Brush Creek. At a point 
 about five miles south of Bainbridge, on Paint Creek, in 
 Ross county, this depression is filled up, from side to side, 
 to a height of about two hundred feet, with a glacial deposit 
 containing numerous northern bowlders and scratched stones. 
 On the northern side, toward Paint Creek, this deposit ex- 
 hibits every mark of a terminal moraine, with its character- 
 
GLACIAL DAMS, LAKES, AND WATERFALLS. 373 
 
 istic knobs, ridges, and kettle-holes ; while to the south of it 
 there is an extensive plain known in the locality as the Beech 
 
 Fio. 110.— Map of a portion of the glacial boundary in southern Ohio, showing its relation 
 to Paint Creek cut-off and to Beech Flate, at the head-waters of Ohio Brush Creelc. 
 The general elevation of the nnglaciated region is from three hundred to five hun- 
 dred feet above the river-bed. The terraced valley of the Scioto Eiver is approxi- 
 mately indicated by the dotted line. The old valley of Paint Creelc, now choked up 
 by glacial debriB, ran around by Slate Mills. The small stream coming in at the angle 
 of the cut-off is the one from which an estimation of time is made in chapter xx, 
 page 661. . 
 
 Flats. This, too, consists largely of transported material from 
 the north ; but it is mostly fine like loess, and level-topped, 
 and is about one hundred feet higher than the valley of 
 Baker's Fork, which heads in it and runs to the south, empty- 
 ing into the Ohio River. 
 
374 THE ICE AGE IX NORTH AMERICA. 
 
 It is evident that, while the ice-front rested over the 
 northveestem portion of Pike county, and was depositing the 
 terminal moraine just described, there ought to have been, 
 during the whole time, a strong current of glacial drainage 
 rushing down through Baker's Fork into Brush Creek, de- 
 positing more or less of overwash gravel along its bed. But 
 there are no marks of such a line of glacial drainage here. 
 There are no terraces on Baker's Fork ; and no granitic peb- 
 bles are to be found in its valley, where they ought to exist 
 in great numbers if there had been a glacial torrent pouring 
 into it from the terminal moraine. The uniformity with 
 which these lines of glacial drainage are marked by terraces, 
 and by the presence of northern pebbles gathered from the 
 glaciated region, is, as we have already seen, one of the most 
 striking features just outside the glaciated region all the way 
 from the Atlantic Ocean to the Mississippi River. For the 
 exception in the present instance there would seem to be but 
 one explanation, and that is as complete as it is unexpected. 
 The ice-dam in the Ohio River, supposed on other evidence 
 to have been in existence for a short time at the climax of 
 the Glacial period, perfectly accounts for this exceptional 
 phenomenon, while no other adequate cause whose existence 
 is at all probable can be found. The explanation is as fol- 
 lows : 
 
 The height above the tide of this moraine, which closes 
 up the opening between Paint and Brush Creeks, is between 
 nine hundred and a thousand feet, corresponding very closely 
 with the supposed height of the water-level produced by the 
 ice-dam at Cincinnati. Hence, during the existence of the 
 dam, there would have been no chance for the formation of 
 a glacial torrent down Brush Creek, since back-water extended 
 to the very ice-front at its head, and the terminal deposit was 
 laid down in still water. The limitations of this deposit at 
 the head of Baker's Fork and the level surface of Beech 
 Flats, therefore, furnish a complete verification of the theory, 
 and prove beyond question the reahty of the Cincinnati dam. 
 
 Furthermore, the lower portion of Paint Creek is so situ- 
 
QLAOIAL DAMS, LAKES, AND WATERFALLS. 375 
 
 ated with reference to the glacial boundary that its mouth 
 was for a time obstructed by the ice ; but, when the ice-front 
 had withdrawn two or three miles, drainage would again be 
 opened into the Scioto, and at a level which is a hundred 
 feet or more lower than the surface of the moraine between 
 Paint and Brush Creeks, so that the natural necessity for a 
 glacial outlet down Brush Creek would exist only so long as 
 the ice closed up the mouth of Paint Creek. From this de- 
 scription of the situation it becomes evident that, so soon as 
 the ice should have retreated from the Kentucky hills south 
 of Cincinnati, so as to raise the blockade and reopen the chan- 
 nel of the Ohio, it would doubtless also have retreated from 
 the mouth of Paint Creek ; and the line of glacial drainage 
 through that into the Scioto, and thence down the reopened 
 Ohio, would have been re-established. 
 
 A theory which so naturally accounts for so complicated 
 a set of facts as these is well-nigh proved by this single in- 
 stance. The only competing hypothesis possible is that of a 
 general subsidence of the country producing the same water- 
 level above Cincinnati which the ice-dam is supposed to have 
 done. But such a theory lacks the positive evidence addu- 
 cible for a glacial dam at Cincinnati ; and, besides, it is not 
 probable that a general depression of the country, such as 
 would produce still water at the head of Brush Creek, would 
 be of such short duration as is implied by the facts connected 
 with this deposit. The gradual lowering of a barrier holding 
 the water at that height would have caused numerous benches 
 on the interior of the deposit toward the ice, whereas the 
 terrace on that side is even more abrupt than on the other. 
 
 A second class of facts supporting the the.ory of the Cin- 
 cinnati ice-dam is drawn from the high-level terraces found in 
 the trough of the upper Ohio and its main tributaries. One of 
 the most significant of these occurs at Pellevue, on the north 
 side of the Ohio Kiver, five miles beftw Pittsburg, where a 
 terrace is found about a mile long, half a mile wide, and fifty 
 or sixty feet in depth, preserved upon a shelf of rock facing 
 the river perpendicularly, and between two hundred and 
 
376 TEE ICE AGE IN NORTH AMERICA. 
 
 fifty and three hundred feet above it. The material of this 
 high-level terrace concists largely of gravel and pebbles de- 
 rived from the glaciated region, granitic pebbles being abun- 
 dant in it. It must therefore have been deposited since the 
 ice came over into the head-waters of the Alleghany. Two 
 theories are offered to account for this : One assumes the 
 reality of the ice-dam at Cincinnati, and sees in this terrace 
 a natural result of that obstruction. Bellevue lies in the 
 lower angle formed by the Junction of the Ohio and Alle- 
 ghany Valleys ; and the summit of the terrace under consid- 
 eration corresponds closely in altitude with the elevation of 
 the Cincinnati dam ; and here, in the eddy below the mouth 
 of the Alleghany, at the beginning of the larger valley of 
 the Ohio, was the natural place for the accumulation of 
 bowlder-laden masses of ice brought down from the glacier's 
 front by the periodical floods of the Alleghany. 
 
 If we leave the theory of general submergence out of 
 account, the only other way to explain this accumulation is 
 to regard it as a portion of a deserted river valley when the 
 stream occupied a rocky bed more than three hundred feet 
 above its present level. This would require a lapse of time, 
 since the deposit was made, sufiBcient to allow the Ohio and 
 all its tributaries to lower their rocky beds, for many hun- 
 dred miles, to a depth of more than three hundred feet. As 
 we shall see, later on, it seems to be entirely out of the ques- 
 tion to suppose any such lapse of time since the last glacial 
 period, for the Magara gorge has receded only seven miles 
 since then. But resort may be had to the supposition of a 
 previous glacial period, during which the ice also came over 
 into the head-vfaters of the Alleghany, and, indeed, every- 
 where came down nearly to the limits of the glaciated region 
 in Pennsylvania and Ohio already delineated. On this sup- 
 position the time intervening between the first and the last 
 glacial period would fte equal to that required by the Ohio 
 and its tributaries to lower their rocky beds at least three 
 hundred or four hundred feet. This enormous lapse of time 
 would carry us back, in all probability, well-nigh to the be- 
 
GLACIAL DAMS, LAKES, AND WATERFALLS. 377 
 
 ginniiig of the Tertiary period. But, that no such length of 
 time can have elapsed since these upper terraces were depos- 
 ited, may be inferred from their structure and situation in 
 various other places. For example, vegetable and animal 
 remains of recent species are found in a very fresh state of 
 preservation in river deposits of the Ohio Valley correspond- 
 ing in age with the terraces in question. 
 
 The first instance of this to be mentioned is one which 
 has been carefully investigated and described by Professor 
 I. C. "White, and occurs on the Monongahela River, near 
 Morgantown, W. Va. The trough of the Monongahela, 
 which joins the Alleghany at Pittsburg to form the Ohio, 
 is in every way similar to that of the Alleghany, with the 
 single exception that the terraces which line its banks at 
 heights corresponding to those of the Alleghany and upper 
 Ohio, contain no pebbles of northern drift, but consist wholly 
 of material which is native to the valley itself. At numer- 
 ous places along the Monongahela there are extensive depos- 
 its of pebbles and bowlders from two hundred to three hun- 
 dred feet above the river, especially near where tributaries 
 enter. In many of these deposits there is nothing to indi- 
 cate their age ; but, at Morgantown, W. Va., there would 
 seem to be a decisive case, showing the comparatively recent 
 date of the deposition of this series of terraces. The follow- 
 ing is Professor White's description : 
 
 Owing to the considerable elevation— ^275 feet — of the fifth 
 terrace above the present river-bed [in the vicinity of Morgan- 
 town], its deposits are frequently found far inland from the 
 Monongahela, on tributary streams. A very extensive deposit 
 of this kind occurs on a tributary one mile and a half north- 
 east of Morgantown ; and the region, which includes three or 
 four square miles, is significantly known as the " Flats." The 
 elevation of the "Flats" is 275 feet above the river, or 1,065 
 feet above tide. The deposits on this area consist almost en- 
 tirely of clays and fine, sandy material, there being very few 
 bowlders intermingled. The depth of the deposit is unknown, 
 since a well sunk on the land of Mr. Baker passed through 
 
378 TEE 10 E AOE IN NORTH AMERICA. 
 
 alternate beds of clay, fine sand, and muddy trash to a depth 
 of sixty-fiye feet without reaching bed-rock. In some portions 
 of the clays which make up this deposit, the leaves of our 
 common forest-trees are found most beautifully preserved. 
 Whether or not they show any variations from the species 
 growing in that region, the writer has not yet had time to 
 determine ; but, when a larger collection has been obtained, 
 this subject will receive the attention that it deserves, since, 
 if the date of the Glacial epoch be very remote, the species 
 must necessarily show some divergence from the present flora. 
 Of animal remains the only fragments yet discovered in this 
 highest of the terraces is the tooth of a mastodon, dug up near 
 Stewartstown, seven miles northeast from Morgantown. 
 
 As the relation of this deposit near Morgantown to others 
 farther up the river is important, we quote also from the sup- 
 plementary statement of facts made by Professor "White in a 
 paper presented at the meeting of the American Association 
 for the Advancement of Science at Buffalo, in 1886 : 
 
 In the region of Morgantown, on the main Monongahela, 
 these terrace deposits end at about 275 feet above low water, 
 or 1,065 feet above tide ; while at Fairmount, twenty -six 
 miles above, there is a vast amount of this terrace material 
 thrown down about the junction of the Valley and West Fork 
 Elvers, and the upper limit of the same is a little over two hun- 
 dred feet above low water, which is here 850 feet above tide. 
 About twenty miles farther up the river (West Fork), near 
 Shinnston, the upper limit of the terrace material is found at 
 160 feet above the water, but here the latter has an elevation 
 of about 885 feet above tide. 
 
 At Clarksburg, where the river unites with Elk Creek, there 
 is a wide stretch of terrace deposits, and the upper limit is there 
 about 1,050 feet above tide, or only 130 feet above low water 
 (920 feet) ; while at Weston, forty miles above (by the river), 
 these deposits cease at seventy feet above low water, which is 
 there 985 feet above tide. It will thus be observed that the 
 upper limit of the deposits retains a practical horizontality 
 from Morgantown to Weston, a distance of one hundred miles, 
 
aiAGIAL DAMS, LAKES, AND WATERFALLS. 379 
 
 since the upper limit has the same elevation above tide (1,045 
 to 1,065 feet) at everj' locality. 
 
 These deposits, consist of rounded bowlders of sandstone, 
 with a large amount of clay, quicksand, and other detrital 
 matter. The country rock in this region consists Of the soft 
 shales and limestones of tlie upper coal-measures, and hence 
 there are many "low gaps" from the head of one littlC'Stream 
 to that of another, Especially along the immediate regiqn of the 
 river ; and in every case the summits of these dividies, where 
 they do not exceed an elevation of 1,050 feet above tide, are 
 covered with transported or terrace material ; but where tlie 
 summits go more thain a few feet above that level we find no 
 transported material upon them, but simply the decomposed 
 country rock. 
 
 A fine example of one of these bowlder-covered divides may 
 be seen at the mouth of the Youghiogheny Eiver, back of Mc- 
 Keesport, Pa. The "divide" in question is one between the 
 water of Long Run, which puts into the Youghiogheny, two 
 miles above McKeesport, and that of another little stream 
 which heads up against it, and flows into the Monongahela 
 within the city limits. The divide between these two water- 
 ways, although 275 feet above the level of the river, is almost 
 imperceptible in a broad and bowlder-covered valley through 
 which there is not the slightest doubt that the waters of the 
 Youghiogheny once flowed during an epoch of submergence.* 
 
 Passing farther down the Ohio Valley, we find a most 
 interesting exhibition of this high-level slack-water depo- 
 sition in Teazes Valley, Putnam county, W. Va. This val- 
 ley runs from the Kanawha River, a little below Charleston, 
 to the Ohio at the mouth of the Guyandotte, near Hunting- 
 ton. The valley is clearly enough a remnant of the early 
 erosion which sculptured the whole country. The water of 
 the upper Kanawha evidently at one time took this course 
 to the Ohio. The valley is very clearly marked, and its 
 mnin features can be taken in by any one riding over the 
 Chesapeake and Ohio Railroad between Huntington and 
 
 * "American Journal of Science," vol. cxxxiv, 1887, pp. 378, 379. 
 
380 
 
 THE 10 E AGE IX yOETU AMERICA. 
 
 Charleston. It is about a mile wide, and from two hundred 
 to three hundred feet lower than the hills on either side, and 
 
 the deposir iit L< 
 r)uriecl piece of wood referred to in the text was about the 
 
 nir Level, in Teazes \'alley. West Virginia. Tlie 
 the text was about the middle of tlie'cnt on dig- 
 tring into the perpendicular face of the bank. 
 
 has a remarkably level tlo(.ir throughout the greater part of 
 its course. The bottom of the vallev is filled throughout 
 
GLACIAL DAMS, LARES, AND WATERFALLS. 381 
 
 with a deposit of river- pebbles covered many feet deep with 
 a mixture of sand and clayey loam. In some places this loam 
 is from thirty to forty feet deep, extending for several miles 
 without interruption, as at Long Level, about the middle of 
 the valley. Here a section, about half a mile long and twenty- 
 five feet deep, shows at the top a stiif stratum of clay con- 
 taining wood at a depth of seven feet. Immediately below 
 is sand cemented together by the intiltrations of iron. The 
 stratum above, containing the wood, had never been disturbed, 
 and the wood is remarkably fresh in its whole appearance. 
 It is scarcely possible that it should have remained in such a 
 position during all the time required for the erosion of the 
 Ohio Valley and its tributaries from the level of Teazes Val- 
 ley to its present level, two hundred and iif ty feet below. 
 Besides, there are many other things to show that the deposit 
 was in slack water rather than on the flood-plain of a running 
 stream. Unlike the deposit of a river on its banks, in this 
 case the silt extends clear across the valley, covering every- 
 thing to a uniform depth, except where it has been removed 
 by subsequent irregular erosion. 
 
 Another evidence of the recent date of this deposit of 
 river-silt in Teazes Valley, as compared with the erosion of 
 the valley itself, appears in the relation of the transverse 
 water-ways to it. Mud River and Hurricane Creek are two 
 small streams rising some little distance to the south, but 
 now either joining the valley, or crossing it at a level sixty 
 or seventy feet lower than that of its rocky bottom. Mud 
 River joins it at Milton, and then turns west and follows its 
 course to the Guyandotte. But the level of Mud River, 
 even where it now joins the valley, is one hundred and 
 twenty feet lower, and this in a channel worn in the solid 
 sandstone rock. Hurricane Creek is a still smaller stream, 
 and crosses the valley within a few miles of its eastern end, 
 emptying into the Kanawha some miles lower down. Where 
 this small stream crosses Teazes Valley its bed is sixty or 
 more feet lower down in the rock than that on which the 
 pebbles and silt rest throughout the valley, and these de- 
 
382 THE ICE AGE IN NORTH AMERIOA. 
 
 posits come down on the rocky shelf bordering the Hurri- 
 cane in a way to show that it could not have remained where 
 it is during the time required for so small a stream to wear 
 down so large and deep a channel. 
 
 The extension of Teazes Valley, after merging for a 
 short distance with the Ohio, really continues back of Ash- 
 land, Ky., on the south side of the river, down as far as 
 opposite Hanging Rock in Ohio, in all a distance of about 
 sixty miles. 
 
 Among other decisive instances discovered by Professor 
 White, and bearing on the recent date of these high-level 
 terrace deposits, are the following : 
 
 About ten miles above the mouth of the Big Sandy Eiver, 
 and on the West Virginia side, a considerable deposit of small 
 water-worn bowlders occurs near the summit of a broad, flat- 
 topped hill, at an elevation of four hundred feet above the 
 stream, or not far from nine hundred feet above tide. This 
 deposit is interesting from the fact that it is the only one that 
 I was able to find between the point in question and the source 
 of the river, nearly two hundred miles above, though the fail- 
 ure may be satisfactorily accounted for in the precipitous char- 
 acter of the bounding valley-walls, and the unusually soft and 
 easily disintegrating nature of all the surface-rocks ; for along 
 the Big Sandy even the Pottsville conglomerate becomes rot- 
 ten, and very readily crumbles into loose sand, which, carried 
 down by the rain, fills up the channel of the river, and has 
 thus given name to the stream. It is not assuming to state 
 that these rounded bowlders of local coal-measure sandstone 
 could hardly have resisted the elements during the long time 
 since the Big Sandy Valley existed at this 400-foot level. 
 
 The Guyandotte River puts into the Ohio next above the 
 Big Sandy, and on this stream, about one hundred miles above 
 its mouth, a large deposit of rounded bowlders was observed 
 on the inner side of one of its great curves opposite the mouth 
 of Panther Creek. The bowlders cease at 150 feet above the 
 stream, or about 935 feet above tide, according to levels run by 
 Captain Miller, of the Trans- Flat Topland Company. The 
 bowlder-deposits are found in greatest quantity about the 
 
GLACIAL DAMS, LAKES, AND WATERFALLS. 383 
 
 junctiou of streams, and consequently at the mouth of Elk 
 River, on the Great Kanawha, in the vicinity of Charleston, 
 vast numbers of them extend to near 350 feet ahove this river 
 (800 feet above tide), and scattering ones are found up to 390 
 feet (or 945 feet above tide). Here, along with the hard rocks 
 of local origin, we find great numbers that have come from the 
 Blue Ridge in Virginia and North Carolina, nearly two hun- 
 dred miles distant. 
 
 I shall not be surprised if some of my readers regard this 
 theory of an ice-dam at Cincinnati as visionary ; and, indeed, 
 I do not myself present it as established with the same de- 
 gree of certainty vrith which the more general facts relating 
 to the Ice age are established. Still, I am confident that 
 close reflection upon the evidence already presented will be 
 sufficient to produce conviction to most minds. The bowl- 
 ders found south of the Ohio Kiver, opposite Cincinnati, are 
 too large to have been carried except by ice, and they are so 
 high above the river, and so far back from it, that floating 
 ice could not have been the agent of transportation, except 
 the channel itself were obstructed. Nor is there any im- 
 probability arising from the nature of the case against such 
 an obstruction by ice. For, through a distance of nearly 
 fifty miles, the ice certainly came down to the northern side 
 of the trough. In much broader valleys than this the ordi- 
 nary ice-gorges during a spring freshet produce remarkable 
 results, raising the water to a great height. But the course 
 of the Ohio at Cincinnati is such as to invite gorges upon the 
 largest scale ; and, with a moving ice-front behind, a perma- 
 nent closure is not improbable. If one should surmise that 
 a depth of five hundred feet of water would lift the ice in 
 the channel so as to secure a subglacial outlet, it should be 
 remembered that the specific gravity of ice is such that it 
 would require more than a depth of six hundred feet of 
 water to lift a body of ice which was seven hundred feet 
 thick ; and the bowlders on the south side of the river are so 
 far distant, the one of which we give a cut being seven or 
 eight miles south of the river, that the ice was doubtless 
 
384 THE ICE AOE IN NORTH AMERICA. 
 
 considerably more than a hundred feet above the top of the 
 trough at Cincinnati. 
 
 Bringing to mind the other considerations, we think no 
 one can doubt that the trough of the Ohio was mainly 
 formed before the Glacial period. This we infer from the 
 enormous lapse of time during which the river had been at 
 work, viz., from the first elevation of the continent to the ear- 
 liest date assigned by any to a glacial period in North Amer- 
 ica. With this trough formed, the problem of accounting 
 for the terrace at Bellevue, below Pittsburg, containing gra- 
 nitic pebbles is a most difficult one, except upon the theory of 
 this ice-dam. The granitic pebbles mark it as connected 
 with the Glacial period, and its height (three hundred feet 
 above the river) renders it impossible of explanation on any 
 other theory than one which assumes an incredible lapse of 
 time since the deposit was made. The small extent to which 
 the material of this terrace has been oxidized and disinte- 
 grated, indicates no such enormous lapse of time ; while the 
 terraces in the Monongahela. River, which Professor White 
 describes as containing freshly preserved leaves at great 
 depths, and the terraces in the neighborhood of the Big 
 Sandy, containing pebbles peculiarly liable to disintegration, 
 confirm the inference of the comparatively recent origin of 
 a series of terraces in the upper Ohio, closely correspond- 
 ing to the level of the Cincinnati ice-dam. To these con- 
 siderations, also, are to be added those concerning Beech 
 Flats, between the southwestern angle of Paint Creek and 
 the head-waters of Brush Creek. Altogether this would 
 seem sufficient to give a high degree of probability to the 
 theory, and to justify the wide acceptance which has been 
 given to it by the eminent geologists most familiar with 
 the region. 
 
 In presenting this brief summary of evidence bearing on 
 the existence of the Cincinnati ice-dam, however, I am far 
 from considering the discussion of the theory closed. It 
 remains for local observers, first, to comprehend the facts 
 already presented, and then to test the hypothesis in every 
 
GLACIAL DAJL'^, LAKES, AND WATEEFALLS. 385 
 
 legitimate uumiier post^ible. The field is a most inviting one, 
 ami will assuredly yield abundant fruits. 
 
 Among other requirements made upon the theory it has 
 been demanded that 1 should point out the outlet of the 
 pent-up waters. But this I am not able at present to do. I 
 have had neither the time nor the opportunity to explore the 
 region south of Cincinnati sniiiciently to say certainly where 
 it was ; nor have I come to a negative conclusion, so that I 
 
 Firj. II:;,— S(jlit Kock. A contilomcratc cniitainini; Kraritic pcliblet 
 Kentucky, about thirty milee below Cincinnati, one hnmlrefl 
 low water. (See text.) 
 
 In Boone Oonnty, 
 h1 '^ixty feet al)Ove 
 
 can say that there is none to be found; nor do 1 know tliat 
 any one else has done so. Professor Claypole is inclined to 
 think Mr. Squier* has indicated the locality of the old outlet 
 in some of the passes in tlie vicinity of Owingsville and 
 Mount Sterling leading from the upper waters of the Lick- 
 ing River into the valley of the upper Kentucky. From 
 
 * See letter in "Science," September 28, 1883 ; for additional facts, see the 
 author's " (Jlacial Boundary in Ohio, Indiana, and Kentucky," [i. SB 
 
^gO ijan, lua j±{^j2i i^\ iiumxi jlju-cihiuji.. 
 
 Gannet's table of levels, which is very scanty in that portion 
 of Kentucky, it would appear that the height of the water- 
 partings between the Licking and the Kentucky is not 
 greater than that of the ridge running south from Cincinnati 
 between the Licking and the Ohio ; so that such an outlet 
 may exist somewhere in that vicinity. 
 
 But 1 have not been sure that the water did not pass 
 around the immediate margin of the ice reaching the Ohio at 
 the mouth of Woolper Creek, about thirty miles below Cin- 
 cinnati, where the celebrated post-glacial conglomerate known 
 as Split Eock is situated. This formation consists of pebbles 
 now firmly cemented together by infiltrations of lime. The 
 mass rises one hundred and sixty feet above the river. The 
 most of the pebbles are limestone from the Cincinnati group, 
 but there are mingled with them granitic pebbles which 
 show it to be a glacial deposit. On Middle Creek, a little 
 lower down in Boone county, the same conglomerate is found 
 at a still higher level, running up to four hundred feet ; and 
 at various places on the road to Big Salt Lick uncemented 
 gravel, which is unquestionably of glacial origin, caps the 
 tops of the hills at about the same height. It is not unlikely, 
 therefore, that much of the outflow from around the dam 
 was in the immediate vicinity of the ice-front. 
 
 Professor E. W. Claypole, in an article* read before the 
 Geological Society of Edinburgh and published in their 
 "Transactions," has given a very vivid description of the 
 scenes connected with the final breaking away of the ice-bar- 
 rier at Cincinnati. He estimates that the body of water held 
 in check by this dam occupied twenty thousand square miles, 
 and that during the summer months, when the ice was most 
 rapidly melting away, it was supplied with water at a rate 
 that would be equivalent to a rainfall of one hundred and 
 sixty feet in a year ! This conclusion he arrives at by esti- 
 mating that ten feet of ice would annually melt from the 
 
 * " The Lake Age in Ohio," " Transactions of the Geological Society of Edin- 
 burgh," IBS'? 
 
GLACIAL DAMS, LAKES, AND WATERFALLS. 387 
 
 portion of the State which was glaciated, and which is about 
 twice the extent of the nngiaciated portion. Ten feet over 
 the glaciated portion is equal to twenty feet of water over 
 the unglaciated. To this must be added an equal amount 
 from the area farther back whose drainage was then into the 
 upper Ohio. This makes forty feet per year of water so con- 
 tributed to this laks-basin. Furthermore, this supply would 
 all be furnished in the six months of warm weather, and to 
 a large degree in the daytime, which gives the rate above 
 mentioned. 
 
 The breaking away of the barrier to such a body of water 
 is no simple affair. As this writer remarks : 
 
 The Ohio of to-day in flood is a terrible danger to the val- 
 ley, but the Ohio then must have been a much more formidable 
 river to the dwellers on its banks. The muddy waters rolled 
 along, fed by innumerable rills of glacier-milk, and often 
 charged with ice and stones. The first warm days of spring 
 were the harbinger of the coming flood, which grew swifter 
 and deeper as summer came, and only subsided as the falling 
 temperature of autumn again locked up with frost the glacier 
 fountains. . . . The ancient Ohio Eiver system was in its 
 higher part a multitude of glacial torrents rushing off the ice- 
 sheet, carrying all before them, waxing strong beneath the ris- 
 ing sun, till in the afternoon the roar of the waters and their 
 stony burden reached its maximum, and, as the sun slowly 
 sank, again diminished, and gradually died away during the 
 night, reaching its minimum at sunrise. . . . 
 
 But, with the steady amelioration of the climate, more vio- 
 lent and sudden floods ensued. The increasing heat of sum- 
 mer compelled the retreat of the ice from the Kentucky shore, 
 where Covington and Newport now lie, and so lowered its sur- 
 face that it fell below the previous outflow-point. The waters 
 then took their course over the dam, instead of passing, as 
 formerly, up the Licking and down the Kentucky River Val- 
 leys. The spectacle of a great ice-cascade, or of long ice-rapids, 
 was then exhibited at Cincinnati. This cataract, or these rap- 
 ids, must have been several hundred feet high. Down these 
 cliffs or this slope the water dashed, meltirg its own channel, 
 
-£• 
 
 R 
 
 J 
 
 Ml^P OIT' 
 
 CUYAHOGA LAKE. 
 
 Area about 55 Sqr. Milesi 
 Scale, 3 miles to 1 inch. 
 
 Strutlura j- G,., Enffr't, K T. 
 
 112a.— Map illustrating a stage in the recession of the ice in Ohio. For a section of 
 the deposit in the bed of this laljelet, see page274. The gravel deposits formed at this 
 stage along the outlet into the Tuscarawas River are very clearly marked (Claypole). 
 {" Transactions of the Edinburgh Geological Society.") """".cu tuiajriiuw;. 
 
OLAOIAL DAMS, LAKES, AND WATERFALLS. 389 
 
 and breaking up the foundations of its own dam. With the 
 depression of the dam the level of the lake also fell. Possibly 
 the change was gradual, and the dam and the lake went gently 
 down together. Possibly, but not probably, this was the case. 
 Far more likely is it that the melting was rapid, and that it 
 sapped the strength of the dam faster than it lowered the 
 water. This will be more probable if we consider the immense 
 area to be drained. The catastrophe was then inevitable — the 
 dam broke, and all the accumulated water of Lake Ohio was 
 poured through the gap. Days or even weeks must have 
 passed before it was all gone ; but at last its bed was dry. The 
 upper Ohio Valley was free from water, and Lake Ohio had 
 passed away. . . . 
 
 But the whole tale is not yet told. Not once only did 
 these tremendous floods occur. In the ensuing winter the 
 dam was repaired by the advancing ice, relieved from the melt- 
 ing effects of the sun and of the floods. Year after year was 
 this conflict repeated. How often we can not tell. But there 
 came at last a summer when the Cincinnati dam was broken 
 for the last time ; when the winter with its snow and ice failed 
 to renew it, when the channel remained permanently clear, and 
 Lake Ohio had disappeared forever from the geography of 
 North America. . . . 
 
 How many years or ages this conflict between the lake and 
 the dam continued it is quite impossible to say, but the quan- 
 tity of wreckage found in the valley of the lower Ohio, and 
 even in that of the Mississippi, below their point of junction, 
 is sufiicient to convince us that it was no short time. "The 
 age of Great Floods" formed a striking episode in the story of 
 the "Retreat of the Ice." Long afterward must the valley 
 have borne the marks of these disastrous torrents, far surpass- 
 ing in intensity anything now known on the earth. The great 
 flood of 1885, when the ice-laden water slowly rose seventy-three 
 feet above low-water mark, will long be remembered by Cincin- 
 nati and her inhabitants. But that flood, terrible as it was, 
 sinks into insignificance beside the furious torrent caused by the 
 sudden, even though partial, breach of an ice-dam hundreds of 
 feet in height, and the discharge of a body of water held behind 
 it and forming a lake of twenty thousand square miles in extent. 
 
390 
 
 THE ICE AGE IN XORTH AMERICA. 
 
 To the human dwellers in the Ohio Valley— for we have 
 reason to believe that the valley was in that day tenanted by 
 man— these floods must have proved disastrous in the extreme. 
 It is scarcely likely that they were often forecast. The whole 
 population of the bottom lands must have been repeatedly 
 swept away ; and it is far from being unlikely that in these 
 and other similar catastrophes in different parts of the world. 
 
 F]G. 113.— Section of the lake ridges near Sandnsky, Ohio. 
 
 which characterized certain stages in the Glacial era. will be 
 found the far-off basis on which rest those traditions of a flood 
 that are found among almost all savage nations, especially in 
 the north temperate zone. 
 
GLACIAL DAMS, LAKES AND WATERFALLS. 391 
 
 Since the above account was written there has been a 
 very animated discussion of the theory, the result of which 
 has been to confirm the general view here maintained, while 
 modifying some of the subsidiary points. Professor T. C. 
 Chamberlin early expressed his disbelief in the dam, and 
 after traversing the Monongahela Valley from Morgantown 
 to Pittsburg expressed his belief that the clay deposits there, 
 which Professor I. C. White had regarded as practically on 
 a water level for a distance of more than 100 miles, were flood 
 plain deposits of a flowing stream descending with the gradient 
 of the valley. As Professor Chamberlin had taken pains to 
 express this view in his introduction to my Bulletin published 
 by the U. S. Geological Survey (No. 54), it became necessary 
 for a committee of the American Association for the Advance- 
 ment of Science to go over the ground with Professor White. 
 The result was that everyone was convinced of the correctness 
 of the facts as stated in my original publication.* It appeared 
 that as Professor Chamberlin did not find Professor White 
 at home, he failed to see the facts which Professor White had 
 recorded. That an ice dam existed which ponded up the water 
 in the Monongahela to a height of more than 1,000 feet above 
 the sea is established beyond all controversy. But its immedi- 
 ate connection with the Cincinnati ice dam is now thrown 
 into the background by the broader considerations already 
 brought to light in discussing the formation of the present 
 Ohio River. 
 
 The following facts detailedinapaperread, by Professor 
 White, before the Geological Society of America, tat the Buf- 
 falo meeting in 1896 are as interesting as they are conclusive 
 in establishing the existence of an ice-dam in the Upper Ohio 
 Valley. At three different points the divide between the Up- 
 per Monongahela basin and the valley of the Ohio, is cut by 
 
 * "Bulletin of the Geological Society of America," vol xiv (1902), 
 p. 4. 
 
 t Published in "Am. Geol.," vol. xviii, Deo. 1896, "Origin of the 
 High Terrace Deposits of the Monongahela River." 
 
392 THE ICE AGE IN NORTH AMERICA. 
 
 abandoned water weirs at an elevation of approximately 1,100 
 feet, above tide. These are just such channels or "cols" as 
 would be cut by the escaping water impounded by an ice-dam 
 which obstructed the northerly drainage of the Monongahela. 
 The terrace deposits of clay, quicksand, sand and gravel, bor- 
 dering the river valley for more than 100 miles below Weston 
 in West Virginia, range from 1,020 to 1,068 feet above tide, 
 while that at Pittsburg is 990 feet above tide. The present 
 river falls 290 feet between Weston and Pittsburg, while 
 the terrace falls only forty feet in 200 miles at Pittsburg, and 
 eight feet at Geneva, 117 miles below Weston. In tabular 
 form the facts are as follows. 
 
 MUES 
 
 
 PRESENT BIVER 
 
 A.T. 
 
 TOP OF DEPOBI 
 A.T. 
 
 
 
 Weston 
 
 990 
 
 1,030 
 
 40 
 
 Clarksburg 
 
 916 
 
 1,020 
 
 75 
 
 Fairmont 
 
 851 
 
 1,067 
 
 101 
 
 Morgantown 
 
 787 
 
 1,038 
 
 117 
 
 Geneva 
 
 772 
 
 1,022 
 
 206 
 
 Pittsburg 
 
 700 
 
 990 
 
 These terraces are specially prominent wherever a tributary 
 comes into the main valley to form a delta at the level of 
 the impounded water. Frequently the clay topping of the 
 terrace is more than sixty feet thick, furnishing material for 
 numerous pottery establishments. 
 
 The following plants were identified by Dr. F. H. Knowl- 
 ton, as occurring in these clay deposits. 1. Equisctum arvense 
 L.; 2. Cyperus sp.; 3. Potamogeton robbinsii Oakes; 4. Ldqui- 
 dambar styracifolia L; 5. Platanus occidentalis L (sycamore) ; 
 6. Ulmus racemosa Thomas (the white elm); 7. Quercus 
 falcata Michigan; 8. Betula nigra L. (black birch); 9. Fagus 
 ferruginea Ait (beech) ; 10. Castanea pumila Mill (chinquapia). 
 All of these are living species, and most of them are still 
 found in the vicinity. But special interest attaches to Potor 
 mogeton robbinsii, of which a great number of fragments of 
 
GLACIAL DAMS, LAKES AND WATERFALLS. 393 
 
 stems and leaves were found. Its present distribution is 
 from New Brunswick to New Jersey, north of Lake Superior 
 and northward. The occurrence of this species in these beds 
 is, as Professor White remarks, of special interest, since it 
 practically demonstrates that there was during glacial times 
 a movement of water from the edge of the ice near Beaver, 
 Pennsylvania, southward along the Monongahela Valley, 
 through the escape weirs just described, which brought with 
 it this northern plant. 
 
 Since as already shown the preglacial drainage of both the 
 upper and the middle portions of the Ohio basin was to the 
 north, it follows that vast sheets of water were ponded up in 
 front of the advancing ice-sheet from the moment that those 
 northern outlets were closed. One of the most prominent of 
 these would be that occupying the basin drained in preglacial 
 times by the Monongahela and Lower Allegheny rivers, which 
 originally flowed off through Beaver Creek and the Grand 
 River valleys into Lake Erie a little east of Ashtabula. This 
 temporary lake would have its level regulated by the height 
 of the col already referred to at New Martinsville, a little 
 below Wheeling, West Virginia. It was in this glacial lake 
 that the deep still water clay deposits described along the 
 Middle Monongahela accumulated. But after a compara- 
 tively short period the col at New Martinsville was worn down 
 so that a permanent line of drainage was opened in that direc- 
 tion and Lake White, as we may be permitted to name it, 
 no longer existed in the Monongahela Valley. 
 
 But as the ice-sheet continued to advance through central 
 and southern Ohio the other lines of northerly drainage were 
 obstructed and other temporary lakes formed which continued 
 until the col, in the Muskingum above Zanesville, and that in 
 the Ohio below the mouth of the Scioto were eroded suffi- 
 ciently to permanently open present lines of drainage. Then, 
 finally, when the ice reached the junction of Mill Creek Valley 
 and the Great Miami at Hamilton, 0., the whole drainage 
 
394 THE ICE AGE IN NORTH AMERICA. 
 
 which had been flowing in that direction was so obstructed 
 that it was turned over the col which existed a little below 
 Cincinnati, and the permanent channel was opened which 
 is now followed by the Ohio River. During this period of 
 erosion there was a temporary lake formed above Cincinnati, 
 but of comparatively short duration, for the immense flow 
 of water from the whole upper basin of the Ohio would work 
 with great rapidity to cut down the col below the city. 
 
 After this there followed in immediate succession, the 
 Cincinnati ice-dam proper, of which an account has been 
 given. For a distance of fifty miles the ice advanced into 
 Kentucky to heights of land fully 500 feet above the present 
 level of the river, and must have obstructed the drainage up 
 to that level. This was doubtless of comparatively short 
 duration, but while it continued it would set the water in 
 the whole valley above to that height, which would submerge 
 Pittsburg to a depth of 300 feet, and reach far up both the 
 Monongahela and the Allegheny rivers. The shortness of 
 its duration, however, makes it difficult to distinguish its 
 deposits from those which had been made during the con- 
 tinuance of the earlier ice-dams. While admitting there- 
 fore, that the "Cincinnati ice-dam" was at first somewhat 
 overworked in accounting for the deposits in the Upper Ohio 
 Valley, it is by no means ruled out of the problem. TheCin- 
 cinnati ice-dam still remains a fact with which all. students 
 of the region are compelled to reckon. 
 
 As already intimated, however, the existence of the Cin- 
 cirmati dam would necessitate an overflow either into the 
 Kentucky River or around the margin of the ice, and such a 
 channel, if it ever existed, should be easily discovered. 
 But though I have diligently searched for it, it has so far 
 eluded observation. This has inclined me to account for 
 the Kentucky deposits as results of annual ice gorges, dur- 
 ing the climax of the period, in the narrow channel below the 
 city. But even so the phenomenon is none the less impres- 
 sive, and would involve the flooding of the upper Ohio and 
 its tributaries to the extent stated. 
 
GLACIAL DAMS, LAKES, AND WATERFALLS. 395 
 
 On coming to the region of the Great Lakes, the influence 
 of ice-barriers is very conspicuous. South of Lake Erie there 
 is an ascending series of what are called lake ridges. These 
 are composed of sand and gravel, and consist largely of 
 local material, and seem to maintain throughout their entire 
 length a definite level with reference to the lake, though 
 accurate measurements have not been made over the whole 
 field. The approximation, however, is sufiiciently per- 
 fect to permit us to speak of them as maintaining a uniform 
 level. These ridges can be traced for scores of miles in a 
 continuous line, and in the early settlement of the country 
 were largely utilized for roads; In Lorain county, Ohio, 
 an ascending series of four ridges can be distinguished at 
 different levels above the lake.* The highest is from 200 
 to 220 feet above it; the next is approximately 150 to 
 160 feet; the next lower is from 100 to 118 feet; and the 
 next lower less than 100 feet, while some appear on the 
 islands near Sandusky which are not over 70 feet above the 
 water-level. Eastward from Buffalo portions of tliis series 
 have been traced, according to Gilbert, until they disappear 
 against the highlands near Alden, on the Erie Railroad. 
 
 Lake Ontario is likewise bordered by similar ridges upon 
 its southern and eiastem sides, but the investigations in that 
 region are not yet complete enough to be altogether satisfac- 
 tory. From what has already been done it is evident that 
 they do not maintain so nearly a uniform level as on the 
 shores of Lake Erie. Mr. G. K. Gilbert, of the United States 
 Geological Survey, informs me that, from the vicinity of 
 Oneida Lake toward the northeast, the ridges rise rapidly 
 with reference to the lake-level, and that to a less extent 
 they rise in a westerly direction, showing that if they were 
 water-deposits, there has been considerable oscillation of the 
 land both northeast and southwest of an axis following the 
 line of the Mohawk Valley. 
 
 That the ridges on Lake Erie mark temporary shore-lines 
 
 * " Geological Survey of Ohio," vol. ii, p. 207. 
 
GLACIAL DAMS, LAKES, AND WATERFALLS 397 
 
 of the lakes can not well be doubted, for they are not related 
 to any great natural lines of drainage, but follow the wind- 
 ings of a definite level, receding from the lake wherever 
 there is a transverse valley, and forming in some cases parallel 
 embankments on either side of such valley, running inland 
 as far as to the general level of the series, and then return- 
 ing on itself upon the other side, to strike off again par- 
 allel %vith the shore at the same level. Their relation to the 
 lake is also shown by the local character of the material. It is 
 usually such as would wash up on the shore out of the rock in 
 place. In the sandstone region the ridges are largely made 
 up of sand, mingled with fragments from the general glacial 
 deposit. Over the regions of outcropping shales the ridges 
 are composed largely of the harder nodules which have suc- 
 cessfully resisted the attrition of the waves. Other evidences 
 that they are shore-deposits are their stratification, the rela- 
 tive steepness of their sides toward the lake, and the frequent 
 occurrence of fragments of wood buried at greater or less 
 depths on their outer margin. 
 
 It need not be said that there has been much speculation 
 concerning the cause which maintained the waters of the 
 lakes at the levels indicated by these ridges, and permitted 
 them to fall from the level of one to that of another in suc- 
 cessive stages, so suddenly as they seem to have done ; for, 
 from the absence of intermediate deposits, it is evident that 
 the formation of one ridge had no sooner been completed, 
 than the one at the next lower level began to form. In the 
 earlier stages of glacial investigation, before the full power 
 and flexibility of glacial ice were appreciated, and before 
 the exact course of the southern boundary of the ice-sheet 
 was known, the elevation of the water to produce these 
 ridges was supposed to have resulted either from a general 
 subsidence of the whole region to the ocean-level, or from 
 the elevation of a rocky barrier across the outlet. Both 
 these theories were attended with insuperable difficulties. 
 In the first place, there is no such amount of collateral evi- 
 dence to support the theory of general subsidence as there 
 
398 THE ICE AGE AV NORTH AMERICA. 
 
 should be if it really had occurred. The subsidence of the 
 lake region to such an extent would have left countless 
 other marks over a wide extent of country ; but such marks 
 are not to be found. Especially is there an absence of 
 evidences of marine life. The cause was evidently more 
 local than that of a general subsidence. The theory of the 
 elevation of a rocky barrier would also seem to be ruled out 
 of the lield by the fact that no other direct evidence can be 
 found of such recent local disturbances. Such facts as we 
 have point to a subsidence at the east rather than to an eleva^ 
 tion. 
 
 But a glance at the course of the terminal moraine, and 
 at the relation of the outlets of these lakes to the great ice- 
 movements of the Glacial period, brings to view a most 
 likely cause for this former enlargement and increase in 
 height of the surface of the lower lakes. It will be no- 
 ticed that the glacial front near New York city was about 
 one hundred miles farther south than it was in the vicinity 
 of Buffalo. Hence the natural outlet to the Great Lakes 
 through the Mohawk Valley would not have been opened 
 until the ice-front over New England and eastern New York 
 had retreated to the north well-nigh one hundred and fifty 
 miles. A similar amount of retreat of the ice-front from 
 its farthest extension in Cattaraugus county, in New York, 
 would have carried it back thirty miles to the north of Lake 
 Ontario, while a similar amount of retreat from eastern Ohio 
 would have left nearly all the present bed of Lake Erie free 
 from glacial ice. With little doubt, therefore, we have, in 
 the lake ridges of Upper Canada, New York, and Ohio, evi- 
 dence of the existence of an ice-barrier which continued to 
 fill the valley of the Mohawk, and choke up the outlet through 
 the St. Lawrence, long after the glacial front farther to the 
 west had withdrawn itself to Canada soil. A study of these 
 ridges may yet shed important light upon the length of time 
 during which this ice-barrier continued across the valley of 
 the Mohawk. 
 
o { 
 
 < / 
 
 3: 
 
 s> 
 
 
 
 { 
 
 ^ 
 
 < 
 
 4 
 
 ^"f"^^^^ t % l^'/' 
 
 
 Fia. 115 — Lake Whittlesey, with, correlative Ice border. (Map by Leverett.) 
 
 Fig. 116— Lake Warren, with probable correlative Ice border. (Map by Leverett.) 
 
 
 
 
 
 Nipissin^ GfeatLake% 
 
 
 
 
 
 with Isobases 
 
 
 
 re^^ 
 
 ^%v. 
 
 Scale 
 
 ■<.;.■ 
 
 < 
 
 
 O L 
 
 
 ^^^r ^'^^ 
 
 
 
 
 ^ 
 
 ^"^dS^ 
 
 
 
 
 V" 
 
 Is 
 
 
 
 '**/ 
 
 -^ 
 
 
 j^, UT^Nlplsslng Great Lakes and Champlaln Sea. Numerous isobases give altitude 
 above sea level of the highest exposed shore. Isobases of Michigan and Huron basins 
 by Taylor and Goldthwalte. 
 
THE GLACIAL LAKE AGASSIZ 
 
 By Wakren Upham, D.Sc, 
 
 St. Paul, Minn. 
 
 As soon as the departing ice-sheet, which had enveloped 
 the northern United States and British America during the 
 glacial period, in its final melting off the land from south to 
 north, receded beyond the water-shed dividing the basin of 
 the Miimesota River from that of the Red River of the North, 
 a lake, fed by the glacial melting, stood at the foot of the ice- 
 fields, and extended northward as they withdrew along the 
 valleys of the Red River to Lake Winnipeg, filling this valley 
 and its branches to the heights of the lowest points over 
 which an outlet could be found. Until the ice-barrier was 
 melted away on the area now crossed by the Nelson River, 
 thereby gradually draining this glacial lake, its outlet was 
 along the present course of the Minnesota River. At first 
 its overfiow was upon the nearly level undulating surface 
 of the drift, 1,050 to 1,125 feet above the sea, at the west 
 side of Traverse and Big Stone counties, Minnesota; but in 
 process of time this cut a channel there, called Brown's 
 Valley, 100 to 150 feet deep and about a mile wide, the highest 
 point of which, on the present water divide between the Missis- 
 sippi and Nelson river basins, is 975 feet above the sea-level. 
 From this outlet the Red River valley plain extends 315 miles 
 north to Lake Winnipeg, which is 710 feet above the sea. 
 Along this entire distance there is a very uniform continuous 
 descent of a little less than one foot per mile. 
 
 The farmers and other residents of this fertile plain are 
 well aware that they live on the area once occupied by a great 
 lake; for its beaches, having the form of smoothly rounded 
 ridges of gravel and sand, a few feet high, with a width of 
 several rods, are observable extending almost horizontally 
 long distances upon each of the slopes which rise east and west 
 of the valley plain. Hundreds of farmers have located their 
 
402 THE ICE AGE IN NORTH AMERICA. 
 
 buildings on these beach ridges as the most dry and sightly 
 spots on their lands, affording opportunity for perfectly drained 
 cellars even in the wettest seasons, and also yielding to wells, 
 dug through this sand and gravel, better water than is usually 
 obtainable in wells on the adjacent clay areas. While each 
 of these farmers, in fact every one living in the Red River 
 Valley, recognizes that it is an old lake bed, few probably 
 know that it has become for this reason a district of special 
 interest to geologists, who have traced and mapped its upper 
 shore along a distance of about 800 miles. 
 
 Numerous explorers of this region, from Long and Keat- 
 ing in 1823, to Gen. G. K. Warren in 1868 and Prof. N. H. 
 Winchell in 1872, recognized the lacustrine features of the 
 valley; and the last named geologist first gave what has been 
 generally accepted as the true explanation of the existence of 
 the lake, namely, that it was produced in the closing stage 
 of the glacial period by the dam of the continental ice-sheet 
 at the time of its melting away. As the border of the ice-sheet 
 retreated northward along the Red River Valley, drainage 
 from that area could not flow as now freely to the north 
 through Lake Winnipeg and into the ocean at Hudson Bay, 
 but was turned by the ice-barrier to flow south across the 
 lowest place on the water-shed, dividingthis basin from that of 
 the Mississippi. This lowest point is found, as before noted, 
 at Brown's Valley on the western boundary of Minnesota, 
 where an ancient water-course, about 125 feet deep and one 
 mile to one and a half miles wide, extends from Lake Traverse, 
 at the head of the Bois des Sioux, a tributary of the Red River, 
 to Big Stone Lake, through which the head stream of the Min- 
 nesota River passes in its course to the Mississippi and the 
 Gulf of Mexico. .; 
 
 Detailed exploration of the shore lines and area of this 
 lake was begun by the present writer for the Minnesota 
 Geological Survey in the years 1879 to 1881, under the direc- 
 tion of Professor N. H. Winchell, the State geologist. In 
 
THE GLACIAL LAKE AGASSIZ. 403 
 
 subsequent years I was employed also in tracing the old lake 
 shores through North Dakota for the United States Geological 
 Survey, and in Southern Manitoba, to the distance of 100 
 miles north from the international boundary to Riding 
 Mountain, for the Geological Survey of Canada. For the 
 last named survey, Mr. J. B. Tyrrell extended the exploration 
 of the lake shore lines more or less completely for 200 miles 
 farther north along the Riding and Duck mountains and the 
 Porcupine and Pasquia hills, west of Lakes Manitoba and 
 Winnipegosis, to the Saskatchewan River. 
 
 This glacial lake was named by me in the eighth annual 
 report of the Minnesota Geological Survey, for the year 
 1879, in honor of Louis Agassiz, the first prominent advocate 
 of the theory of the formation of the drift by land ice; and the 
 outflowing river, whose channel is now occupied by Lakes 
 Traverse and Big Stone and Brown's Valley, was named also 
 by me, in a paper read before the American Association for the 
 Advancement of Science at its Minneapolis meeting in 
 1883, the River Warren, in commemoration of General War- 
 ren's admirable work in the United States Engineering Corps, 
 in publishing maps and reports of the Minnesota and Missis- 
 sippi River surveys. 
 
 Descriptions of Lake Agassiz and the River Warren are 
 somewhat fully given in the eighth and eleventh annual reports 
 of the Minnesota Geological Survey, and in the first, second, 
 and fourth volumes of its final report. Three other special re- 
 ports of my explorations of Lake Agassiz were published; the 
 first in 1887, as Bulletin No. 39, of 84 pages, with a map, by 
 the Geological Survey of the United States; the second in 
 1890, by that of Canada, in its Annual Report, New Series, 
 vol. iv, for 1888-89, forming Part E, 156 pages, with maps and 
 sections; and last, this subject was most fully issued by the 
 U. S. Geological Survey, as its Monograph XXV, 1895, a 
 quarto volume of 658 pages and 38 plates (maps, views, and 
 sections). 
 
404 THE ICE AGE IN NORTH AMERICA. 
 
 Several successive levels of the ancient lake are recorded by 
 distinct and approximately parallel beaches, due to the gradual 
 lowering of the outlet by the erosion of the channel at Brown's 
 Valley, and these are named principally from stations on the 
 Breckenridge and Wahpeton line of the Great Northern 
 Railway, in their descending order, the Herman, Norcross, 
 Tintah, Campbell, and McCauleyville beaches, because they 
 pass through or near these stations and towns. 
 
 The highest or Herman beach is traced in Minnesota from 
 the northern end of Lake Traverse eastward to Herman, and 
 thence northward, passing a few miles east of Bamesville, 
 through Muskoda, on the Northern Pacific Railway, and 
 around the west and north sides of Maple Lake, which lies 
 about twentj' miles east — southeast of Crookston, beyond 
 which it goes eastward to the south side of Red and Rainy 
 lakes. In North Dakota the Herman shore lies about four 
 miles west of Wheatland, on the Northern Pacific Railway, and 
 the same distance west of Larimore, on the Pacific line of the 
 Great Northern Railway. On the international boundary, in 
 passing from North Dakota into Manitoba, this shore coin- 
 cides with the escarpment or front of the Pembina Mountain 
 plateau, and beyond passes northwest to Brandon on the 
 Assiniboine River, and thence northeast to the Riding 
 mountain. 
 
 Leveling along this highest beach shows that Lake Agassiz, 
 in its earliest and highest stage, was nearly 200 feet deep above 
 Moorhead and Fargo; a little more than 300 feet deep above 
 Grand Forks and Crookston; about 450 feet above Pembina, 
 St. Vincent, and Emerson; more than 500 feet above the 
 city of Winnipeg; and about 500 and 600 feet, respectively, 
 above Lakes Manitoba and Winnipeg. The length of Lake 
 Agassiz is estimated to have been nearly 700 miles, and its 
 area not less than 110,000 square miles, exceeding the com- 
 bined areas of the five great lakes tributary to the St. Lawrence. 
 
THE GLACIAL LAKE AGASSIZ. 406 
 
 When the ice-barrier was so far melted back as to give out- 
 lets northeastward lower than the River Warren, other 
 beaches marking these lower levels of the glacial lake were 
 formed; and finally, by the full departure of the ice, Lake 
 Agassiz was drained away to its present representative. Lake 
 Winnipeg. 
 
 The rate of the northward ascent of the originally level 
 highest beach, within the area of my leveling, varied from 
 about six inches per mile near its southern end to about one 
 foot per mile along the greater part of its extent to southern 
 Manitoba. On the east side of the Red River Valley the old 
 shores are higher than on its west side, the rate of ascent from 
 west to east being about half as much as from south to north. 
 The direction of maximum ascent of the planes of the former 
 lake levels is therefore toward the north-northeast. Farther 
 north several beaches of the series mapped by Tyrrell along 
 the bases of the Riding and Duck mountains have a northward 
 rise of two or three feet per mile. The changes of level were 
 in progress and were nearly completed during the existence 
 of Lake Agassiz, as is shown by the gradual diminution in 
 the northward ascent of the successive lower beaches, until 
 the latest and lowest differs only slightly from perfect hori- 
 zontality. 
 
 Gravitation of Lake Agassiz toward the ice-sheet accounts 
 for a small part of the present inclination of the beaches. 
 Changes in the temperature of the earth's crust due to the 
 glacial period and its termination produced a still smaller 
 effect, but this tended to give the opposite slope, or a descent 
 toward the north. Upward movement of this great land area, 
 resulting from its being unburdened by the departure of the 
 ice-sheet, was the chief element in the causes of the differential 
 changes in the height of this basin. Flow of the plastic inner 
 part of the earth's mass, restoring its equilibrium or isostasy, 
 uplifted first the southern half of the area of Lake Agassiz, 
 from Lake Traverse to Gladstone in Manitoba; next it raised 
 
406 THE ICE AGE IN NORTH AMERICA. 
 
 the northern half of the lake area, while the region at the south 
 was almost at rest; and finally, during the recent epoch, after 
 the whole basin of LakeAgassiz was passed by this wave like 
 permanent uplift, it has been elevating the basin of Hudson 
 Bay, where the movement appears to be still in progress. 
 Pleistocene oscillations of the land in many other parts of 
 the world have been independent of glaciation, or these have 
 been combined with movements due to the accumulation of 
 ice-sheets and to their removal; but the uplifting of the basins 
 of Lake Agassiz and Hudson Bay is apparently attributable 
 wholly to the departure of the ice-sheet. 
 
 The entire duration of Lake Agassiz, estimated from the 
 amount of its wave action in erosion and in the accumulation 
 of beach gravel and sand, appears to have been only about 
 1,000 years; and the time of its existence and of the end of the 
 ice age is thought, from the rate of recession of the Falls of 
 St. Anthony, cutting the post-glacial gorge of the Mississippi 
 River from Fort Snelling to Minneapolis, to have been some- 
 where between 6,000 and 10,000 years ago. 
 
CETAPTEE XYL 
 
 THE LOESS. 
 
 The deposit called loess received its name in Germany, 
 where it was first described. Bat its most remarkable devel- 
 opments are in China and in America. The formation is 
 one of great interest in every respect. It furnishes the most 
 fruitful soil in the world, and is extensively used for the ex- 
 cavation of houses in China and in some parts of America. 
 At the same time it presents the scientific observer with a 
 most attractive but puzzling problem. Professor Pumpelly, 
 who has seen it in all parts of the world, gives the following 
 lucid description of the deposit : 
 
 This remarkable formation covers several hundred thousand 
 square miles in northern China, and larger areas in the rest of 
 Asia. It forms the soil also over an immense area in the west- 
 ern United States. Its thickness varies in China up to two 
 thousand feet, and to one hundred and fifty and two hundred 
 feet in Europe and America. 
 
 Loess is a calcareous loam. It is easily crushed in the band 
 to an almost impalpable powder, and yet its consistency is such 
 that it will support itself for many years in vertical cliffs two 
 hundred feet high. A close examination shows that it is filled 
 with tubular pores branching downward like rootlets, and that 
 these tubes are lined with carbonate of lime. It is to these 
 that it owes its consistency and its vertical internal structure. 
 It is wholly unstratifled, and often where erosion has cut into 
 it, whether one foot or one hundred yards, the walls are ab- 
 solutely vertical. Its vertical internal structure causes it to 
 break off in any vertical plane, but in no other. Hence, when 
 26 
 
408 THE IGE AGE IN NORTE AMERICA. 
 
 a cliff is undermined, the loess breaks off in immense vertical 
 plates leaving again a perpendicular wall. , 
 
 It is divided into beds varying in thickness from one foot 
 to two or three hundred, which thin out to nothing at the bor- 
 ders and are separated by parting planes. These planes are 
 marked by angular debris near the mountains, and by elon- 
 gated upright calcareous concretions elsewhere. 
 
 This remarkable combination of softness with great strength 
 and stability of exposed surfaces is of inestimable value in a 
 woodless country. In Asia, thousands of villages are excavated 
 in a most systematic manner at the base of clifEs of loess. 
 Doors and windows pierced through the natural front give 
 light and air to suites of rooms which are separated by natural 
 walls, and plastered with a cement made from the loess concre- 
 tions. These are the comfortable dwellings of many millions 
 of Chinese fanners, and correspond to the ruder dug-outs of 
 Nebraska. 
 
 To the same qualities is due the fact that the loess districts 
 of China are exceedingly fertile plains, in each of which a rap- 
 idly progressing erosion has excavated the most labyrinthine 
 valley systems, in which all the members, down to the smallest 
 tributaries, are sunk with vertical walls to depths of from one 
 hundred to several hundred feet. Even the wagon-roads be- 
 come in time depressed to a depth of fifty feet and more by the 
 removal of the dust by wind. 
 
 There is one more peculiarity of the loess : it not only is 
 wholly unstratified, but it contains the remains of only land- 
 animals and especially of land-snails. Alexander Braun ex- 
 amined 211,968 specimens of shells from the loess of the Rhine 
 between Basle and Bonn, and found that all were land-snails 
 except only thirty-three individuals, consisting of Limnma, 
 Planoriis, and Vitrina, which came from three isolated points 
 in the valley of the Rhine and Neckar. 
 
 Baron Richthofen, after prolonged study of the loess of 
 China, propounded the theory that it was a wind-deposit, 
 consisting of material which had resulted from the slow dis- 
 integration of the rocks in the arid regions of central Asia, 
 from which the westerly winds have been continually blow- 
 
THE LOESS. 409 
 
 ing for an untold period. As applicable to China, Kicht- 
 liofen's theory is perhaps adequate. Mr. Pumpelly is also 
 inclined to accept the theory as applicable to America, re- 
 marking that — 
 
 No one can realize the capacity of wind as a transporter of 
 fine material who has not lived through at least one great storm 
 on a desert. In such a simoon the atmosphere is lilled with a 
 driving mass of dust and sand which hides the country under 
 a mantle of impenetrable darkness, and penetrates every fabric ; 
 it often destroys life by suffocation, and leaves in places a deposit 
 several feet deep. 
 
 The prevailing westerly wind, carrying sand, carves and pol- 
 ishes the rocky crest of the Sierra Nevada, and, as Mr. King 
 tells me, has formed long wind-stream deltas — if I may coin 
 the term — in the form of lofty sand ranges stretching from 
 each pass eastward, far out on the desert. 
 
 The often cited instances of far-driven volcanic ashes show 
 the ability of the wind to carry comparatively coarse dust 
 through distances of several hundred miles, but it does not 
 seem improbable that the finer particles may remain suspended 
 while the wind makes a complete circuit of the globe. I wit- 
 nessed on March 31st and April 1st, in 1863, a dust-fog at 
 Nagasaki which lasted two days, and left only a just percepti- 
 ble film of dust, observable only on the white, newly painted 
 deck of a yacht. A similar fall occurred simultaneously at 
 Shanghai, and both were contemporaneous with a terrific dust- 
 storm which during two days shrouded the country about 
 Tientsin in deep darkness. 
 
 I am indebted again to Mr. Clarence King for the state- 
 ment that dust-fogs occur on the coast of California with the 
 prevailing west wind ; and this may be, as he suggests, the 
 finest residuum of the loess-dust of an Asiatic dust-storm.* 
 
 Concerning the power of wind to transport dust, many 
 other striking illustrations have been noted. Showers of red- 
 dish dust occasionally fall upon ships far out at sea. Darwin 
 describes one such storm encountered by him near the Cape 
 
 * "American Journal of Science," vol. cxvii, 1879, pp. 133, 134, 139. 
 
410 THE ICE AGE IN NORTH AMERICA. 
 
 Yerds, which was estimated to be sixteen hundred miles 
 broad. A similar shower which passed over the southern 
 part of France in 1846 is estimated by Ehrenberg to have 
 deposited nearly a million pounds of dust. On examination 
 he found that about one eighth of it consisted of microscopic 
 organisms, many of which belonged in South America, thus 
 showing that the wind had blown the dust across the Atlan- 
 tic. In 1835 volcanic dust was blown from Guatemala to 
 Jamaica, a distance of eight hundred miles. 
 
 The main diflBculty of applying the wind theory to account 
 for the loess of the Mississippi Valley and of Europe lies in 
 its definite relation to water-levels. For example, in the 
 Rhine Yalley the loess rests in places upon elevations of 
 eight hundred feet above the river, but does not occur at 
 higher levels. This would clearly indicate that it is a water- 
 deposit. The problem has been to conceive how the water 
 could be maintained at that level in the valley of the Rhine ; 
 and the theory has been put forth, and ably defended by 
 Geikie and others, that the Rhine and other rivers emptying 
 into the North Sea were obstructed at their mouths by the 
 Scandinavian glaciers, and so the water was ponded back 
 toward the Alps to the level at which the loess ceases. 
 
 The absence of fossils of aqueous origin in the loess may 
 be accounted for in two ways : 1. If the deposit took place, 
 as was supposed, in temporary glacial lakes, there may have 
 been no species existing in them to have left their remains. 
 This would be likely to be the case for three reasons : (1) 
 the lakes were of only temporary continuance ; (2) the tem- 
 perature of the water must have been abnormally low; and 
 (3) the superabundance of silt might interfere with animal 
 life. 2. Professor Hilgard has suggested that the porosity 
 of the loess, which favors the continual presence and percolar 
 tion of water charged with acids throughout its mass, renders 
 it almost certain that any inclosed fossils would have been 
 rapidly dissolved. As to why this oxidizing and dissolving 
 process should have selected fossils of aqueous origin, and 
 made an exception in favor of those of terrestrial animals. 
 
THE LOESS. 411 
 
 Professor Hilgard explains that the terrestrial fossils are, as 
 a matter of fact, found near the marginal portion of the loess, 
 where the destructive processes are least. Whether, also, 
 there may not be a dift'ereuee between the destructibility of 
 land- and fresh-water shells is also a question. The occur- 
 rence of nodules of lime throughout the mass points to such 
 a work of solution and redistribution by water. In regard to 
 the frequent occurrence of the bones of the larger land-ani- 
 mals, Professor Hilgard remarks: "That the phosphatic 
 bones should not have dissolved as easily as the mere carbon- 
 ate shells is readily intelligible ; and as regards their mode of 
 occurrence in the loess of the lower Mississippi they are 
 
 Fig. 119. — Stratilication of the loese in a railway cut at Plattsrnoiilli. Nebraska, at a duptli 
 of eighty-four feet from the surface. (From photograpli furnished by Dr. \. L. 
 Child, of Kansas City, Mo.) (Chamberlin.) (United States Geological Survey.) 
 
 always very much scattered, many bones belonging to the 
 same individual being rarely found together, but seeming to 
 have drifted widely apart. It is not easy to see how the 
 cumbrous bones of the mammoth could have been widely 
 separated in a subaerial deposit." * 
 
 * "American Journal of Science," vol. exviii, 1879, p. 110. 
 
412 THE ICE AGE IN NORTH AMERICA. 
 
 It is to President Ciiamberlin, again,* that we are in- 
 debted for the most careful study of this problem in the Mis- 
 sissippi Valley. According to him, the loess is limited pre- 
 dominantly to the river valleys, and the belt is ordinarily not 
 over forty miles in width. As a rule, also, it is thicker and 
 slightly coarser in character near the banks of the great riv- 
 ers, and there shows some signs of stratification. 
 
 A comparison of loess with sand and clay reveals some 
 interesting facts. The loess is intermediate in size and fine- 
 ness. When the particles are suspended in water, the loess 
 settles much more rapidly than clay — as much of the loess 
 settling in four hours as of the clay in thirty-six hours. Out 
 of 150,000 particles of loess examined under the microscope, 
 146j000, or about ninety-seven per cent, were less than "005 
 of a milHmetre in diameter. A grain of sand one millimetre 
 in diameter is considered fine. But this would make 200,000 
 particles of loess of the size mentioned, and 100,000 particles 
 of the fineness of a large part of true clay. The size of the 
 largest particles of loess noted by President Chamberlin was 
 about one tenth of a millimetre in size, and consisted of scales 
 of mica. The loess of Vicksburg is a little finer than that of 
 Kansas City, and both a little finer than that from the Rhine. 
 The particles of loess were found to be angular and irregular. 
 " Sharp comers and rough surfaces are the rule, and any ap- 
 proach to regularity or smoothness is the exception." In 
 the vicinity of the great rivers the grains are coarser than at 
 points removed from them. In chemical composition the 
 difference between loess and true residual clays is not very 
 striking ; but, as compared with glacial clays, occurring in the 
 till, there is a marked difference in several respects. The glar 
 cial clays have far less amount of silica and alumina, and a far 
 larger amount of calcic and magnesian oxides and of carbonic 
 dioxides. The glacial clays are evidently the result largely 
 of mechanical abrasion ; but the loess would seem to consist 
 in larger proportion of material resulting from chemical dis- 
 
 * " Driftless Area of the Upper Mississippi Valley," pp. 278-307. 
 
THE LOESS. 413 
 
 integration. But the amount of kaolinized products is nearly 
 four times as great in the residnarj clays as in glacial clays or 
 loess. 
 
 The altitude of the loess deposits in the Northwest is by 
 no means uniform, and its variations present great theoretic 
 difficulties. In the lower part of the Mississippi Yalley it is 
 limited to a height of about two hundred and fifty feet. In 
 the upper Mississippi Valley, however, it rises to a height of 
 seven hundred feet above the bed of the river. To account 
 for this, the first impulse would be to suppose a general de- 
 pression of the northern region. But this theory is excluded 
 by various irregularities in this region itself. For example, 
 the loess rises much higher upon the west side of the upper 
 Mississippi than upon the east side, especially in the vicinity 
 of the driftless area of Wisconsin. 
 
 To explain this it is necessary to resort to a rather com- 
 plex theory. In part, perhaps, the peculiar distribution of 
 loess is attributable to a period of general northerly depres- 
 sion during the Glacial epoch. This apparent depression, 
 however, was probably not caused wholly by an oscillation 
 of the crust of the earth itself, since it is shown that it may 
 be due in some degree to the attraction of the ice which had 
 accumulated to the north. Mr. E. S. Woodward, of the 
 United States Geological Survey, has worked out the prob- 
 lem of attraction and its influence in producing a higher level 
 of water at the north, on the supposition that the ice-sheet 
 was ten thousand feet thick, and covered an area to the north 
 2,600 miles in diameter, and finds that the possible influence 
 of such attraction might change the water level at the ice- 
 margin thirty-eight degrees from its center as much as 573 
 feet. But the elevation of the loess attains a height in Iowa 
 and Wisconsin of 1,285 feet. This theory of change of the 
 water-level by glacial attraction, therefore, though not ade- 
 quate, very evidently comes in for a part of the credit of pro- 
 ducing the puzzKng facts relating to the deposition of loess.* 
 
 * "Driftless Area of the Upper Mississippi Valley," pp. 291-301. 
 
414 THE ICE AGE IN NORTH AMERICA. 
 
 A noticeable phenomenon west of the driftless area in 
 Wisconsin and Iowa is that the loess is thickest near the east- 
 em margin of the ice-lobe which passed southward through 
 central Iowa. The distance from the driftless area to the 
 Missouri River, or the width of this lobe in the latitude of 
 Milwaukee, is not far from three hundred and forty miles. 
 It is urged that the presence of an ice-lobe over that region 
 may have had influence in elevating the loess deposits. Since 
 attraction varies inversely as the square of the distance, such 
 a mass of ice near at hand would slightly raise the water along 
 its margin. The objection to this is that the wider ice-lobe 
 to the east did not produce corresponding influence. 
 
 Among the more fruitful supplementary hypotheses 
 brought in to aid in the solution of this part of the prob- 
 lem is to be mentioned that of glacial dams similar to those 
 already alluded to in Europe. In this country the principal 
 fleld in which they may have existed is where it is most 
 needed, namely, west of the Mississippi. An examination 
 of our map will at once suggest that it is possible for much 
 of the loess in northeastern Kansas and eastern Nebraska to 
 have accumulated in temporary lakes formed by glacial dams 
 across the mouth of the Kansas and Platte Rivers, or even of 
 the Missouri itself. How far this cause may have operated 
 remains yet to be determined. 
 
 So complicated are the facts pertaining to the loess as 
 they now appear, that it is not likely that, for some time to 
 come, investigators will arrive at a perfect agreement con- 
 cerning its manner of deposition. Those, however, who 
 have most attentively studied glacial phenomena may be par- 
 doned if they work the glacial hypothesis for all that it is 
 worth. The existence of the vast body of ice which covered 
 the glaciated area introduces a very complicated and efficient 
 cause which it is exceedingly difficult to eliminate from the 
 problem; and it is as allowable for the glacialist to take 
 refuge in supposed ice-dams, where their existence is possible 
 and can not be disproved, as for the ordinary geologist to sup- 
 pose vast orographic changes. The study of the loess has 
 
THE LOESS. 415 
 
 not come so much within my own field of observation as 
 other glacial deposits have done. Still, in southern Indiana 
 and Illinois, and in western Iowa and eastern Nebraska, I have 
 been able to study many typical regions of this deposit ; and 
 the more attention I have given to the subject, the more I 
 have been led to magnify the agencies of the Ice period in 
 producing the results both positive and negative. I have 
 come, therefore, to set an increasingly high estimate upon 
 the suggestions of Mr. ITpham, made after he had concluded 
 his survey of the terminal moraine in Minnesota, Iowa, and 
 eastern Dakota : 
 
 When the ice-sheet extended to the Coteau du Missouri, 
 the Coteau des Prairies, and the Kettle-Moraine, the floods 
 formed by its summer meltings were carried southward by the 
 present avenues of drainage, the streams which occupied the 
 areas between its great lobes in order from west to east being 
 the Big Sioux, Mississippi, and Wisconsin Eivers. The vast 
 glaciers which were gathered up on the Eocky Mountains, and 
 the ice-fields which sloped downward to their termination at 
 the coteaus and the moraine north and east in Minnesota and 
 Wisconsin, supplied every summer immense floods laded 
 with silt, sand, and gravel, that had been contained in the 
 melting ice. Very extensive deposits of modified drift were 
 thus spread along the course of the swollen Missouri and Mis- 
 sissippi. The Orange sand and gravel, described by Professor 
 E. W. Hilgard and others in the lower Mississippi Valley, ap- 
 pear to have been deposited in this way, but during the earlier 
 Glacial epoch, when an ice-sheet reached in Dakota beyond 
 the Missouri Kiver to a termination forty miles west and 
 twenty miles southwest of Bismarck, into northeastern Kansas, 
 half-way across the State of Missouri, and nearly to the Ohio 
 River. 
 
 In the closing stages of this epoch, and during the time 
 succeeding, till the date of the terminal moraine of the coteaus, 
 and especially at the final retreat of t?ie iCe-sheet of this later 
 epoch, the deposition of the overlying, finely pulverized, are- 
 naceous and calcareous silt, called the Bluff formation, or loess, 
 took place. This covers considerable areas along the Mis- 
 
416 THE IGE AGE IN NORTE AMERICA. 
 
 sissippi from southeastern Minnesota to its mouth ; but its 
 greatest thickness and extent are found in the basin of the 
 Missouri River from southern Dakota to its junction with the 
 Mississippi, and upon the region crossed by the Platte or 
 Nebraska River, its longest tributary from the west, which 
 takes its head-waters from a large district of the Rocky Mount- 
 ains. The continuity of this formation from the borders of 
 the ice-sheet and the glaciers of the Rocky Mountains to the 
 shores of the Gulf of Mexico, the absence from it of marine 
 shells, and the presence of land- and fresh-water shells, indicate 
 that its deposition was by slowly descending floods, uplifted 
 upon the surface of this sediment which was being accumu- 
 lated during every summer through a long epoch, in the same 
 manner that alluvium is now spread upon the bottom-lands of 
 our rivers at their times of overflow. The occurrence of the loess 
 in Guthrie, Carroll, Sac, and Buena Vista counties * in Iowa, 
 covering the region next west of the terminal moraine, with its 
 surface fifty feet above these drift-hills and one hundred above 
 the undulating area of till adjoining their east side, proves that 
 during the time of deposition of this part of the loess the ice- 
 sheet extended to this limit, and was a barrier preventing the 
 waters by which this sediment was brought from flowing over 
 the lower area of till that reaches thence east to the Des 
 Moines River. When the ice-sheet retreated beyond the water- 
 shed of the Missouri basin, the principal source of these floods 
 and their sediment was removed, and the subsequent work of 
 the rivers which cross the area of the loess has been to excavate 
 their present valleys or channels, bounded by bluffs of this 
 formation. \ 
 
 A supplementary hypothesis to account for the subsidence 
 assumed by some is, that a bodily depression of the crust of 
 the earth was produced by the weight of the glacier. If one 
 is inclined at first thought to reject this cause as inoperative 
 because of its relative insignificance, he should reflect that 
 
 * " The Ninth Annual Report of the Geological and Natural History Survey 
 of Minnesota," p. 307 et seq. 
 t Ibid., pp. SS?, 8."58. 
 
THE LOESS. 417 
 
 the forces maintaining the present contour of the earth's sur- 
 face may be very evenly balanced, so that a slight addition 
 at one point, and subtraction from another, might be the de- 
 cisive influence in turning the scale. It is now pretty gener- 
 ally believed that the long-continued and steady periods of 
 subsidence involved in the formation of extensive sediment- 
 ary rocks was due to the constant accumulation of the silt, 
 out of which the rocks are made. This silt was relieving the 
 continents of its weight, and adding to the weight along the 
 whole line of deposition. During the Glacial period the 
 transference of water from the ocean to accumulate as ice 
 upon land removed an immense pressure from the ocean- 
 beds, and added an equal amoimt of weight to the glaciated 
 area. How much influence this may have had in depressing 
 temporarily this area and its margin, we are unable to tell. 
 But it is one of those unknown causes in the field which may 
 be supposed to have accomplished something. 
 
 Professor Alexander Winchell has, in a recent interesting 
 paper, suggested a correlation between this pressure of the ice 
 over the glaciated region and the enormous outflows of lava 
 along the Rocky Mountains and the Cascade Range on the 
 Pacific slope.* The lavarbeds of that region are enormous in 
 extent and are certainly of very recent date, and seem to 
 have poured out from long fissures instead of craters. Under- 
 neath these beds there are, in CaUfomia and Oregon, glacial 
 deposits; and it is in these lava-covered glacial deposits of 
 southern California that human remains are supposed by 
 "Whitney to have been found. Professor Winchell's theory 
 connecting those lava outflows with the depression produced 
 by the ice of the Glacial period in the east would relieve 
 the subject of considerable embarrassment arising from the 
 chronological difficulties that have been suggested. To the 
 superficial objection that pressure over the Mississippi Valley 
 would not produce volcanic eruptions at so great a distance 
 
 * " Some Effect of Pressure of a Continental Glacier," in " The American 
 Geologist," March, 1888, pp. 139-143. 
 
418 THE ICE AGE IN NORTH AMERICA. 
 
 as the Pacific coast, it is readily answered : " The terrestrial 
 globe in some of its behavior may be compared to an India- 
 rubber ball filled with water. If indented by pressure in one 
 place, there must be a protuberance equal in volume in 
 another place. In a ball of uniform composition, the pro- 
 tuberance would be spread over the entire surface beyond 
 the region indented, and the effect in one particular spot 
 might be insignificant. Should a small area of the caout- 
 chouc be thinner than the rest, that part would be protruded 
 to a greater extent than other parts of the surface. Should 
 there be small holes or fissures through it, the water would 
 escape and flow over the surface — that is, the protuberance 
 resulting from local pressure would be chiefly on the outside 
 of the shell. As we ordinarily conceive it, the water would 
 be squeezed out like the juice of a squeezed orange."* 
 
 Another supplementary theory which has been invoked 
 to account for the loess, is, that it has, in certain sections 
 at least, been brought to the surface by the agency of earth- 
 worms and other animals which burrow in the ground. The 
 remarkable facts adduced by Mr. Darwin concerning the ac- 
 tivity of these humble agents give respectability to the 
 theory ; and, indeed, the power of these agencies can be seen 
 by any observer who will take the pains to notice the count- 
 less marks of angle- worms which frequently appear upon the 
 STirface of the soil after a rain. Mr. Darwin estimated that 
 the amount of soil brought to the surface by worms was in 
 one case at the rate of nearly two tenths of an inch a year. 
 It is estimated, also, by competent authority, that the number 
 of worms to an acre is as great as fifty-four thousand and 
 that they would weigh three hundred and fifty-six pounds. 
 Trustworthy estimates also show that these creatures some- 
 times raise annually to the surface fourteen tons, and again 
 eighteen tons, to the acre.f From this it is easily seen that 
 the predominance of fine earth upon the surface is due to the 
 
 * "Some Effect of Pressure of a Continental Glacier,'' p. 139. 
 
 f See Darwin, on " Vegetable Mould and Earth-Worms," chaps, iii and iv. 
 
THE LOESS. 419 
 
 work of such animals as worms, crayfish, and ants. But these 
 creatures are limited in the depth to which they can pene- 
 trate the soil and convey it to the surface. StQl, it is not im- 
 probable that in many places where the loess-like deposits are 
 shallow it may be the result of these agencies. 
 
 The twenty years which have elapsed since this chapter 
 was written have been marked by continuous discussion of 
 this puzzling problem of the loess. But its solution seems still 
 about as far distant as ever. The Richthofen theory which 
 accounts for its accumulation and distribution by wind has 
 now more supporters than ever. But there is still a large 
 residuum of facts that resist explanation on that theory alone. 
 The loess of China has doubtless accumulated in the mountain- 
 ous region bordering on Mongolia through the agency of 
 wind, which has brought it in from the desert wastes which 
 stretch westward to the "roof of the World" in Central 
 Asia. But even so it is a question whether the material was not 
 ultimately of glacial origin. 
 
 In the revised edition of Geikie's "Great Ice Age" it is rep- 
 resented that an ice field covered eastern Mongolia which would 
 presumably furnish the reqfuired glacial grist. But after the 
 demonstration that eastern Mongolia never supported ice 
 fields, the glacialists were compelled to resort to the theory 
 that the wind had brought the material across the desert of 
 Gobi, all the way from the base of the mountains, which on 
 three sides surround the Tarim Valley. Here during the 
 glacial period there was a great extension of glaciers in the 
 Pamir and in the Tian Shan and the Himalaya mountams. 
 It is to the floods pouring from the fronts of these glaciers that 
 some would look for the supply of loess which the winds 
 have brought iiito the mountain border of eastern Mongolia. 
 It is difiicult to say that this cause is not adequate to the effect, 
 for the prevailing winds are westerly over this whole region 
 and loess when once started could easily be driven at succes- 
 sive stages for any required distance. I can add my personal 
 
420 THE ICE AGE IN NORTH AMERICA. 
 
 testimony to the extent and effects of the dust storms in east- 
 ern Mongolia, where for a day at a time the dust raised by 
 the wind was so dense that objects could not be distinguished 
 half way across the road. And I have described immense drifts 
 of loess near the summits of the mountains in that region five 
 thousand feet above the sea, where it was impossible to invoke 
 the agency of water to account for the accumulation. 
 
 But the investigations of Huntington and others seem to 
 show that loess is not exclusively of glacial origin, but may 
 be the finer product of subaerial disintegration, such as is 
 going on all the while in desert regions such as exist in Central 
 Asia and in the Rocky Mountain plateau. Still, whatever 
 be the ultimate origin of the material, and however much 
 influence we may attribute to the wind in transporting it , 
 from its original place of formation, water must be allowed 
 a large share in its final distribution, and its accumulation 
 belongs to a definite period corresponding to that of the glacial 
 period. It is perfectly evident to one who traverses the moun- 
 tainous region of eastern Mongolia that loess is not now 
 accumulating there through the agency of wind as fast as it 
 is being removed by water, and carried down to the lower 
 levels of the Yangtsi and Hoang rivers, and by them distrib- 
 uted along the shores of the Chinese Sea. At the same time 
 there are numerous level-topped areas of loess of great size 
 all over northwestern China which indicate deposition by 
 water. 
 
 The same is true of the loess in the Mississippi and Mis- 
 souri valleys. While it is doubtless true that in many places 
 the accumulations are due to wind, it is equally evident that 
 there are many level-topped areas of loess along the borders 
 of the Missouri which betoken the height reached by the 
 overflowing floods of the stream when, as already shown, it 
 was gorged by silt-laden water from the melting ice in the 
 closing stages of the glacial period. Both wind and water 
 had their share in the distribution. The absence of true 
 
THE LOESS. 
 
 421 
 
 water species of shells iu the loess is what we should expect 
 ill an accumulation which took place in periodical or annual 
 overflows. Land snails stUl love the flood-plains of variable 
 streams. In the vicissitudes of the last stages of the glacial 
 period we nave the temporary presence of water jirovided for 
 to suit the habits of such shells as are found in the loess. 
 
 Fig, 120. — Deep gulley in theloess at Helena, Arkansas, 
 vey. Photo, by A. F. Crlder. 
 
 Courtesy of U. S. CJoo. Sur- 
 
CHAPTER XVII. 
 
 FLIGHT OF PLAIfTS AND ANIMAIB DUEING THE GLACIAL 
 
 AGE. 
 
 Among the most interesting incidental effects of the Gla- 
 cial period is that of its influence in distributing plants and 
 animals over the lower latitudes. A glance at a polar pro- 
 jection of the northern hemisphere shows to what a remark- 
 able extent the land is clustered around the north pole, and 
 how easy it would have been, under favorable conditions of 
 climate, for plants and animals to spread from that vicinity 
 along different meridians, till, in the lower latitudes, they 
 should be on opposite sides of the earth. In conformity 
 with these natural lines of emigration, it has long been 
 known that both among plants and animals the species of 
 the northern hemisphere are much more closely allied than 
 those of the southern hemisphere, where no such land-^con- 
 nection exists ; and, as we shall presently see, the problem 
 presented by the distribution of plants in the northern hemi- 
 sphere is very complex and curious. For its solution we are 
 largely indebted to the sagacity of the late Professor Asa 
 Grray, who discovered the key in the influence of the Glacial 
 period. 
 
 In 1857, after he was already familiar, from private cor- 
 respondence, with Darwin's theory of the origin of species, 
 Professor Gray was called upon to study the extensive botan- 
 ical collections brought back from Japan by the expeditions 
 of Commodores Perry and Rodgers. Comparison of these 
 species with those in corresponding latitudes in other por- 
 tions of the world brought out clearly — what had been 
 
FLIOET OF PLANTS AND ANIMALS. 
 
 423 
 
 before but dimly perceived — that there was a remarkable 
 resemblance between the existing plants of eastern Asia and 
 those of eastern North America, that more species are com- 
 mon to Japan and Europe than to Japan and western North 
 
 America, and that the resemblance is greatest of all between 
 Japan and eastern North America. Out of three hundred 
 species, common to the temperate regions of eastern j* sia 
 
424 TEE ICE AGE IN NORTH AMERICA. 
 
 arid the corresponding region of North America, only one 
 third is represented in western North America. 
 
 The key applied by Professor Gray for the solution of 
 this problem was suggested by the investigations of Heer and 
 others, which had brought out the fact that, during the Ter- 
 tiary period, just before the beginning of the Ice age, a tem- 
 perate climate, corresponding to that of latitude 35° on the 
 Atlantic coast, extended far up toward the north pole, per- 
 mitting Greenland and Spitzbergen to be covered with trees 
 and plants similar, in most respects, to those found at the 
 present lime ia Virginia and North Carolina. Here, indeed, 
 in close proximity to the north pole, were then residing, in 
 harmony and contentment, the ancestors of nearly all the 
 plants and animals which are now found in the north tem- 
 perate zone, and here they would have continued to stay but 
 for the cold breath of the approaching Ice age, which drove 
 them from their homes, and compelled them to migrate to 
 more hospitable latitudes. 
 
 The picture of the flight and dispersal of these forests, 
 and of their struggle to find, and adjust themselves to, other 
 homes, is second in interest to that of no other migration. 
 A single tree is helpless before such a force as an advancing 
 glacier, since a tree alone can not migrate. But a forest of 
 trees can. Trees can " take to the woods " when they can 
 do nothing else, and so escape unfavorable conditions. 
 There is a natural climatic belt to which the life of a forest 
 is adjusted. In the present instance, as the favorable con- 
 ditions near the poles were disturbed by the cooling influ- 
 ences of the glacier approaching from the north, the indi- 
 vidual trees on that side of the forest-belt gradually perished; 
 but, at the same time that the favorable conditions of life 
 were contracting on the north, they were expanding on the 
 south, so that along the southern belt the trees could gradu- 
 ally advance into new territory, and so the whole forest-belt 
 move southward, following the conditions favorable to its 
 existence. It is therefore easy to conceive how, with the 
 slow advance of the glacial conditions from the north, the 
 
FLIGHT OF PLANTS AND ANIMALS. 425 
 
 vegetation of Greenland and Britisli America was transferred 
 far down toward the torrid zone on botll tlie Eastern and the 
 Western Continent. Being once thus transferred, the forest 
 would be compelled to remain there until the retreat of the 
 ice began again to modify the conditions so as to compel a 
 corresponding retreat of plants toward their original north- 
 ern habitat. Thus it is that these descendants of the pre- 
 glacial plants of Greenland, arrested in their northward 
 march, have remained the characteristic flora of the latitudes 
 near the glacial boundary. On the other hand, the arctic 
 species, which can not endure even a temperate climate, and 
 which must have accompanied the advancing glacier south- 
 ward, found their natural conditions again in two ways : 1. 
 By following closely upon the steps of the retreating ice to 
 extreme northern latitudes ; and, 2. To use Professor Gray's 
 happy expression, by " taking to the mountains," and finding 
 near their summits the necessary arctic conditions. It is 
 thus that the mountains of !New England and Labrador con- 
 tain many species of plants nearly identical with those on the 
 Alps in Europe. 
 
 No better presentation of this subject can be given than 
 that of Professor Gray himself, made in an address delivered 
 in 1878, and which by the kindness of Mrs. Gray I am per- 
 mitted in large part to reproduce in this connection : * 
 
 The forests of the whole northern hemisphere in the tem- 
 perate zone (those that we are concerned with) are mainly 
 made up of the same or similar hinds. Not of the same spe- 
 cies, for rarely do identical trees occur in any two or more 
 widely separated regions ; but all round the world in our zone 
 the woods contain pines and firs and larches, cypresses and 
 junipers, oaks and birches, willows and poplars, maples and 
 ashes, and the like. Yet, with all these family likenesses 
 throughout, each region has some peculiar features, some trees 
 by which the country may at once be distinguished. 
 
 * " Forest Geography and Archaeology," a lecture delivered before the Har- 
 yard tJniTersity Natural History Society, April 18, 1878, by Asa Gray. Frinted 
 in the "American Journal of Science," vol. oxvi, pp. 85-94, 183-196. 
 
426 THE lOE AGE IN NORTH AMERIUA. 
 
 Begiiming by a comparison of our Pacific with our Atlan- 
 tic forests, it is to be noted that the greater part of the trees 
 familiar on the Atlantic side of the continent are conspicu- 
 ously absent from the Pacific forests. 
 
 For example, the Pacific coast has no magnolias, no tulip- 
 tree, no papaw, no linden or basswood, and is very poor in 
 maples ; no locust-trees — neither flowering locust nor. honey- 
 locust — nor any leguminous tree ; no cherry large enough for 
 a timber-tree, like our wild black cherry ; no gum-trees {Nyssa 
 nor Liquidambar), nor sorrel-tree, nor kalmia ; no persimmon, 
 or bumelia ; not a holly ; only one ash that may be called a 
 timber-tree ; no catalpa or sassafras ; not a single elm, nor 
 hackberry ; not a mulberry, nor planer-tree, nor maclura ; not 
 a hickory, nor a beech, nor a true chestnut, nor a hornbeam ; 
 barely one birch-tree, and that only far north, where the differ- 
 ences are less striking. But as to coniferous trees, the only 
 missing type is our bald cypress — the so-called cypress of our 
 Southern swamps — and that deficiency is made up by other 
 things. But as to ordinary trees, if you ask what takes the 
 place in Oregon and California of all these missing kinds, 
 which are familiar on our side of the continent, I must answer 
 nothing, or nearly nothing. There is the madrofla (Arbutus) 
 instead of our kalmia (both really trees in some places) ; and 
 there is the California laurel instead of our Southern red bay- 
 tree. Nor in any of the genera common to the two does the 
 Pacific forest equal the Atlantic in species. It has not half as 
 many maples, nor ashes, nor poplars, nor walnuts, nor birches, 
 and those it has are of smaller size and of inferior quality ; it 
 has not half as many oaks, and these and the ashes are of so 
 inferior economic value that (as we are told) a passable wagon- 
 wheel can not be made of California wood, nor a really good 
 one in Oregon. . . . 
 
 N"ow almost all these recur, in more or less similar but not 
 identical species, in Japan, north China, etc. Some of them 
 are likewise European, but more are not so. Extending the 
 comparison to shrubs and herbs, it more and more appears 
 that the forms and types which we count as peculiar to our 
 Atlantic region, when we compare them, as we first naturally 
 
FLIOET OF PLANTS AND ANIMALS. 427 
 
 do, with Europe and with our West, have their close counter- 
 parts in Japan and north China ; some in identical species 
 (especially among the herbs), often in strikingly similar ones, 
 not rarely as sole species of peculiar genera or in related ge- 
 neric types. I was a very young botanist when I began to notice 
 this, and I have from time to time made lists of such instances. 
 Evidences of this remarkable relationship have multiplied year 
 after year, until what was long a wonder has come to be so 
 common that I should now not be greatly surprised if a Sarra- 
 cenia or a Dionma, or their like, should turn up in eastern 
 Asia. Very few such isolated types remain without counter- 
 parts. It is as if !N"ature, when she had enough species of a 
 genus to go round, dealt them fairly, one at least to each quar- 
 ter of our zone ; but when she had only two of some peculiar 
 kind gave one to us and the other to Japan, Manchuria, or the 
 Himalayas ; when she had only one, divided these between the 
 two partners on the opposite side of the table. As to number 
 of species generally, it can not be said that Europe and Pacific 
 North America are at all in arrears ; but, as to trees, either the 
 contrasted regions have been exceptionally favored or these 
 have been hardly dealt with. There is, as I have intimated, 
 some reason to adopt the latter alternative. 
 
 We may take it for granted that the indigenous plants of 
 any country, particularly the trees, have been selected by cli- 
 mate. Whatever other influences or circumstances have been 
 brought to bear upon them, or the trees have brought to bear 
 on each other, no tree could hold its place as a member of any 
 forest or flora which is not adapted to endure even the extremes 
 of the climate of the region or station. But the character of 
 the climate will not explain the remarkable paucity of the 
 trees which compose the indigenous European forest. That is 
 proved by experiment, suflRciently prolonged in certain cases 
 to Justify the inference. Probably there is no tree of the north- 
 ern temperate zone which will not flourish in some part of 
 Europe. Great Britain alone can grow double or treble the 
 number of trees that the Atlantic States can ; in all the latter 
 we can grow hardly one tree of the Pacific coast. England 
 supports all of them, and all our Atlantic trees also, and like- 
 wise the Japanese and north Siberian species, which do thrive 
 
428 THE ICE AGE IN NORTH AMERIOA. 
 
 here remarkably in some parts of the Atlantic coast, especially 
 the cooler temperate ones. The poverty of the European sylva 
 is attributable to the absence of our Atlantic American types, 
 to its haying no magnolia, liriodendron, asimina, negundo, no 
 ^schulus, none of that rich assemblage of leguminous trees 
 represented by locusts, honey-locusts, gymnocladus, and cla- 
 drastis (even its cercis, which is hardly European, is like the 
 Californian one mainly a shrub) ; no Nyssa, nor Liquidambar ; 
 no Ericacem rising to a tree ; no bumelia, catalpa, sassafras, 
 Osage orange, hickory, or walnut ; and, as to conifers, no hem- 
 lock, spruce, arbor- vitae, taxodium, nor Torreya. As compared 
 with northeastern Asia, Europe wants most of these same 
 types, also the ailantus, gingko, and a goodly number of conif- 
 erous genera. I can not point to any types tending to make 
 up the deficiency — that is, to any not either in east North 
 America or in northeast Asia, or in both. Cedrus, the true 
 cedar, which comes near to it, is only north African and Asian. 
 I need not say that Europe has no Sequoia, and shares no spe- 
 cial type with California. 
 
 Now, the capital fact is, that many and perhaps almost all 
 of these genera of trees were well represented in Europe 
 throughout the later Tertiary times. It had not only the same 
 generic types, but in some cases even the same species, or what 
 must pass as such, in the lack of recognizable distinctions be- 
 tween fossil remains and living analogues. Probably the Eu- 
 ropean Miocene forest was about as rich and various as is ours 
 of the present day, and very like it. The Glacial period came 
 and passed, and these types have not survived there, nor re- 
 turned. Hence the comparative poverty of the existing Eu- 
 ropean sylva, or at least the probable explanation of the ab- 
 sence of those kinds of trees which make the characteristic 
 difference. 
 
 Why did these trees perish out of Europe, but survive in 
 America and Asia ? Before we inquire how Europe lost them, 
 it may be well to ask how it got them. How came these 
 American trees to be in Europe ? And among the rest, how 
 came Europe to have Sequoias, now represented only by our two 
 big trees of California ? It actually possessed two species and 
 more ; one so closely answering to the redwood of the Coast 
 
FLIGHT OF PLANTS AND ANIMALS. 429 
 
 Eanges, and another so very like the Sequoia gigantea of the 
 Sierra Nevada, that, if such fossil twigs with leaves and cones 
 had been exhumed in California instead of Europe, it would 
 confidently be affirmed that we had resurrected the veritable 
 ancestors of our two giant trees. Indeed, so it may probably 
 be. Gcelum non animam mutant, etc., may be applicable even 
 to such wide wanderings and such vast intervals of time. If 
 the specific essence has not changed, and even if it has suffered 
 some change, genealogical connection is to be inferred in all 
 such cases. . . . 
 
 I take it that the true explanation of the whole problem 
 comes from a just general view, and not through piecemeal 
 suppositions of chances. And I am clear that it is to be found 
 by looking to the north, to the state of things at the arctic 
 2one — first, as it now is, and then as it has been. 
 
 North of our forest regions comes the zone unwooded from 
 cold, the zone of arctic vegetation. In this, as a rule, the 
 species are the same round the world ; as exceptions, some are 
 restricted to a part of the circle. 
 
 The polar projection of the earth down to the northern 
 tropic shows to the eye — as our maps do not — how all the lands 
 come together into one region, and how natural it may be for 
 the same species, under homogeneous conditions, to spread 
 over it. When we know, moreover, that sea and land have 
 varied greatly since these species existed, we may well believe 
 that any ocean-gaps, now in the way of equable distribution, 
 may have been bridged over. There is now only one consid- 
 erable gap. 
 
 What would happen if a cold period were to come on from 
 the north, and were very slowly to carry the present arctic cli- 
 mate, or something like it, down far into the temperate zone ? 
 Why, just what has happened in the Glacial period, when the 
 refrigeration somehow pushed all these plants before it down 
 to southern Europe, to middle Asia, to the middle and southern 
 part of the United States ; and, at length receding, left some 
 part of them stranded on the Pyrenees, the Alps, the Apennines, 
 the Caucasus, on our White and Rocky Mountains, or wherever 
 they could escape the increasing warmth as well by ascending 
 mountains as by receding northward at lower levels. Those 
 
430 THE lOE AQE IN NORTH AMERICA. 
 
 that kept together at a low leyel, and made good their retreat, 
 form the main body of present arctic vegetation. Those that 
 took to the mountains had their line of retreat cut off, and 
 hold their positions on the mountain-tops under cover of the 
 frigid climate due to elevation. The conditions of these on 
 different continents or different mountains are similar but not 
 wholly alike. Some species proved better adapted to one, some 
 to another, part of the world : where less adapted, or less 
 adaptable, they have perished ; where better adapted, they con- 
 tinue — with or without some change — and hence the diversifi- 
 cation of Alpine plants as well as the general likeness through 
 all the northern hemisphere. 
 
 All this exactly applies to the temperate-zone vegetation, 
 and to the trees that we are concerned with. The clew was 
 seized when the fossil botany of the high arctic regions came 
 to light ; when it was demonstrated that in the times next pre- 
 ceding the Glacial period — in the latest Tertiary — ^from Spitz- 
 bergen and Iceland to Greenland and Kamchatka, a climate 
 like that we now enjoy prevailed, and forests like those of New 
 England and Virginia, and of California, clothed the land. 
 We infer the climate from the trees ; and the trees give sure 
 indications of the climate. 
 
 I had divined and published the explanation long before I 
 knew of the fossil plants. These, since made known, render 
 the inference sure, and give us a clear idea of just what the 
 climate was. At the time we speak of, Greenland, Spitzbergen, 
 and our arctic sea-shore, had the climate of Pennsylvania and 
 Virginia now. It would take too much time to enumerate the 
 sorts of trees that have beea identified by their leaves and 
 fruits in the arctic later Tertiary deposits. 
 
 I can only say, at large, that the same species have been 
 found all round the world ; that the richest and most exten- 
 sive finds are in Greenland ; that they comprise most of the 
 sorts which I have spoken of, as American trees which once 
 lived in Europe — magnolias, sassafras, hickories, gum-trees, 
 our identical Southern cypress (for all we can see of difference), 
 and especially Sequoias—noi only the two which obviously 
 answer to the two big trees now peculiar to California, but sev- 
 eral others ; that they equally comprise trees now peculiar to 
 
FLIGHT OF PLANTS AND ANIMALS. 431 
 
 Japan and China, three kinds of gingko-trees, for instance, one 
 of them not evidently distinguishable from the Japan species 
 which alone survives ; that we have evidence not merely of 
 pines and maples, poplars, birches, lindens, and whatever else 
 characterize the temperate-zone forests of our era, but also of 
 particular species of these, so like those of our own time and 
 country, that we may fairly reckon them as the ancestors of 
 several of ours. Long genealogies always deal more or less in 
 conjecture ; but we appear to be within the limits of scientific 
 inference when we announce that our existing temperate trees 
 came from the north, and within the bounds of high proba- 
 bility when we claim not a few of them as the originals of 
 present species. Remains of the same plants have been found 
 fossil in our temperate region, as well as in Europe. 
 
 Here, then, we have reached a fair answer to the question 
 how the same or similar species of our trees came to be so dis- 
 persed over such widely separated continents. The lands all 
 diverge from a polar center, and their proximate portions — 
 however different from their present configuration and extent, 
 and however changed at different times — were once the home 
 of those trees, when they flourished in a temperate climate. 
 The cold period which followed, and which doubtless came on 
 by very slow degrees during ages of time, must long before 
 its culmination have brought down to our latitudes, with the 
 similar climate, the forest they possess now, or rather the 
 ancestors of it. During this long (and we may believe first) 
 occupancy of Europe and the United States, were deposited in 
 pools and shallow waters the cast leaves, fruits, and occasion- 
 ally branches, which are imbedded in what are called Miocene 
 Tertiary, or later deposits, most abundant in Europe, from 
 which the American character of the vegetation of the period 
 is inferred. Geologists give the same name to these beds in 
 Greenland and southern Europe, because they contain the 
 remains of identical and very similar species of plants ; and 
 they used to regard them as of the same age on account of this 
 identity. But in fact this identity is good evidence that they 
 can not be synchronous. The beds in the lower latitudes must 
 be later, and were forming when Greenland probably had very 
 nearly the climate which it has now. 
 
432 THE ICE AOE IW NORTH AMERICA. 
 
 Wherefore the high, and not the low, latitudes must be 
 assumed as the birthplace of our present flora, and the present 
 arctic Tegetation is best regarded as derivative of the temperate. 
 This flora, which, when circumpolar, was as nearly homogene- 
 ous round the high latitudes as the arctic vegetation is now, 
 when slowly translated into lower latitudes, would preserve its 
 homogeneousness enough to account for the actual distribution 
 of the same and similar species round the world, and for the 
 original endowment of Europe with what we now call Ameri- 
 can types. It would also vary or be selected from by the in- 
 creasing differentiation of climate in the divergent continents 
 and on their different sides in a way which might well account 
 for the present diversification. From an early period the sys- 
 tem of the winds, the great ocean-currents (however they may 
 have oscillated north and south), and the general proportions 
 and features of the continents in our latitude (at least, of the 
 American Continent), were much the same as now, so that 
 species of plants, ever so little adapted or predisposed to cold 
 winters and hot summers, would abide and be developed on 
 the eastern side of continents, therefore in the Atlantic United 
 States and in Japan and Manchuria : those with preference 
 for milder winters would incline to the western sides ; those 
 disposed to tolerate dryness would tend to interiors or to re- 
 gions lacking summer rain. So that, if the same thousand 
 species were thrust promiscuously into these several districts, 
 and carried slowly onward in the way supposed, they would 
 inevitably be sifted in such a manner that the survival of the 
 fittest for each district might explain the present diversity. 
 
 Besides, there are resiftings to take into the account. The 
 Glacial period or refrigeration from the north, which at its 
 inception forced the temperate flora into our latitude, at its 
 culmination must have carried much or most of it quite beyond. 
 To what extent displaced, and how far superseded by the vege- 
 tation which in our day borders the ice, or by ice itself, it is 
 difficult to form more than general conjectures, so different 
 and conflicting are the views of geologists upon the Glacial 
 period. But upon any, or almost any, of these views it is safe 
 to conclude that temperate vegetation, such as preceded the 
 refrigeration, and has now again succeeded it, was either thrust 
 
FLIGHT OF PLANTS AND ANIMALS. 433 
 
 out of northern Europe and the northern Atlantic States or 
 was reduced to precarious existence and diminished forms. It 
 also appears that, on our own continent at least, a milder cli- 
 mate than the present, and a considerable submergence of land, 
 transiently supervened at the north, to which the vegetation 
 must have sensibly responded by a northward movement, from 
 which it afterward receded. 
 
 All these vicissitudes must have left their impress upon 
 the actual vegetation, and particularly upon the trees. They 
 furnish probable reason for the loss of American types sus- 
 tained by Europe. 
 
 I conceive that three things have conspired to this loss : 
 1. Europe, hardly extending south of latitude 40°, is all within 
 the limits generally assigned to severe glacial action. 3. Its 
 mountains trend east and west, from the Pyrenees to the Car- 
 pathians and the Caucasus beyond, near its southern border ; 
 and they had glaciers of their own, which must have begun 
 their operations, and poured down the northward flanks, while 
 the plains were still covered with forest on the retreat from 
 the great ice-wave coming from the north. Attacked both on 
 front and rear, much of the forest must have perished then 
 and there. 3. Across the line of retreat of those which may 
 have flanked the mountain-ranges, or were stationed south of 
 them, stretched the Mediterranean, an impassable barrier. 
 Some hardy trees may have eked out their existence on the 
 northern shore of the Mediterranean and the Atlantic coast. 
 But, we doubt not, taxodium and Sequoias, magnolias, and 
 Liquidambars, and even hickories and the like, were among the 
 missing. Escape by the east, and rehabilitation from that 
 quarter until a very late period, was apparently prevented by 
 the prolongation of the Mediterranean to the Caspian, and 
 thence to the Siberian Ocean. If we accept the supposition 
 of Nordenskiold, that, anterior to the Glacial period, Europe 
 was " bounded on the south by an ocean extending from the 
 Atlantic over the present deserts of Sahara and central Asia 
 to the Pacific," all chance of these American types having 
 escaped from or re-entered Europe from the south and east is 
 excluded. Europe may thus be conceived to have been for a 
 time somewhat in the condition in which Greenland is now. 
 
434 TEE ICE AGE IN NORTH AMERICA. 
 
 and, indeed, to have been connected with Greenland in this 
 or in earlier times. Such a junction, cutting off access of the 
 Gulf Stream to the Polar Sea, would, as some think, other 
 things remaining as they are, almost of itself give glaciation 
 to Europe. Greenland may be referred to, by way of compari- 
 son, as a country which, having undergone extreme glaciation, 
 bears the marks of it in the extreme poverty of its flora, and 
 in the absence of the plants to which its southern portion, 
 extending six degrees below the Arctic Circle, might be entitled. 
 It ought to have trees, and might support them. But, since 
 destruction by glaciation, no way has been open for their re- 
 turn. Europe fared much better, but suffered in its degree 
 in a similar way. 
 
 Turning for a moment to the American Continent for a 
 contrast, we find the land unbroken and open down to the 
 tropic, and the mountains running north and south. The 
 trees, when touched on the north by the on-coming refrigera- 
 tion, had only to move their southern border southward, along 
 an open way, as far as the exigency required ; and there was 
 no impediment to their due return. Then the more southern 
 latitude of the ITnited States gave great advantage over Eu- 
 rope. On the Atlantic border, proper glaciation was felt only 
 in the northern part, down to about latitude 40°. In the in- 
 terior of the country, owing doubtless to greater dryness and 
 summer heat, the limit receded greatly northward in the Mis- 
 sissippi Valley, and gave only local glaciers to the Rocky 
 Mountains ; and no volcanic outbreaks or violent changes of 
 any kind have here occurred since the types of our present 
 vegetation came to the land. So our lines have been cast in 
 pleasant places, and the goodly heritage of forest-trees is one 
 of the consequences. 
 
 The still greater richness of northeastern Asia in arboreal 
 vegetation may find explanation in the prevalence of particu- 
 larly favorable conditions, both ante-glacial and recent. The 
 trees of the Miocene circumpolar forest appear to have found 
 there a secure home ; and the Japanese Islands, to which most 
 of these trees belong, must be remarkably adapted to them. 
 The situation of these islands — analogous to that of Great 
 Britain, but with the advantage of lower latitude and greater 
 
FLIGHT OF PLANTS AND ANIMALS. 435 
 
 snnshine — their ample extent north and south, their diversified 
 confignration, their proximity to the great Pacific Gulf Stream, 
 by which a vast body of warm water sweeps along their accentu- 
 ated shores, and the comparatively equable diffusion of rain 
 throughout the year, all probably conspire to the preservation 
 and development of an originally ample inheritance. 
 
 The case of the Pacific forest is remarkable and paradoxi- 
 cal. It is, as we know, the sole refuge of the most character- 
 istic and wide-spread type of Miocene Coniferce, the Sequoias; 
 it is rich in coniferous types beyond any country except Japan ; 
 in its gold-beftring gravels are indications that it possessed, 
 seemingly down to the very beginning of the Glacial period. 
 Magnolias and beeches, a true chestnut, Liquidambar, elms, 
 and other trees now wholly wanting to that side of the conti- 
 nent, though common both to Japan and to Atlantic North 
 America. Any attempted explanation of this extreme paucity 
 of the usually major constituents of forest, along with a great 
 ■development of the minor or coniferous element, would take 
 us quite too far, and would bring us to mere conjectures. 
 
 Much may be attributed to late glaciation ; something to 
 the tremendous outpours of lava which, immediately before 
 the period of refrigeration, deeply covered a very large part of 
 the forest area ; much to the narrowness of the forest-belt, to 
 the want of summer rain, and to the most unequal and pre- 
 carious distribution of that of winter. 
 
 Upon all these topics questions open which we are not pre- 
 pared to discuss. I have done all I could hope to do in one 
 lecture if I have distinctly shown that the races of trees, like 
 the races of men, have come down to us through a prehistoric 
 (or pre-natural-historic) period ; and that the explanation of 
 the present condition is to be sought in the past, and traced in 
 vestiges, and remains, and survivals ; that for the vegetable 
 kingdom also there is a veritable archaeology. 
 
 As the truth of a theory needs to be tested by the meth- 
 od of difference as well as of agreement, we turn to inquire 
 if it be not true that all mountains which reach above the 
 snow-line have an Alpine flora, and whether it be not the 
 conditions themselves which determine the peculiarities? 
 
436 TEE ICE AGE IN NORTH AMERICA. 
 
 These questions are answered by an appeal to certain oceanic 
 islands whicli were outside the influence of continental glacia- 
 tion. According to Wallace, a striking proof of the theory 
 presented by Professor Gray " is found on the Peak of Ten- 
 erifEe, a mountain 12,000 feet high. In the uppermost 4,500 
 feet of this mountain above the limit of trees, Von Buch 
 found only eleven species of plants, eight of which were 
 peculiar ; but the whole were allied to those found at lower 
 elevations. On the Alps or Pyrenees, at this elevation, 
 there would be a rich flora comprising hundreds of arctic 
 plants ; and the absence of anything corresponding to them 
 in this case, in which their ingress was cut oflE by the sea, is 
 exactly what the theory leads us to expect." * 
 
 On both continents, at the close of the Tertiary period, 
 there occurred a remarkable extinction of animals which is 
 doubtless connected with the advance of the continental ice- 
 sheet. Among these we may mention two species of the 
 cat family as large as lions ; four species of the dog family, 
 some of them larger than wolves ; two species of bears ; a 
 walrus, found in Virginia ; three species of dolphins, found 
 in the Eastern States ; two species of the sea-cow, found in 
 Florida and South Carolina; six species of the horse; the 
 existing South American tapir ; a species of the South Amer- 
 ican llama ; a camel ; two species of bison ; three species of 
 sheep ; two species of elephants and two of mastodons ; a 
 species of Megatherium, three of Megalonyx, and one of 
 Mylodon — huge terrestial sloths as large as the rhinoceros, or 
 even as large as elephants, which ranged over the Southern 
 States to Pennsylvania, and the Mylodon as far as the Great 
 Lakes and Oregon. f 
 
 This wondrous assemblage of animals became extinct upon 
 the approach of the Glacial period, as their remains are all 
 found in posl^Pliocene deposits. The intermingling of forms 
 is remarkable. The horses, camels, and elephants which 
 
 * " The Geographical Distribution of Animals,'' vol. i, p. 43. 
 t Ibid., p. 129. 
 
FLIGHT OF PLANTS AND ANIMALS. 437 
 
 lived in North America before the Glacial period were found 
 subsequent to the Glacial period only in the Old World, 
 while the llamas, tapirs, and gigantic Edendata are South 
 American types. The progress of events seems to have been 
 about as follows : In the warm period preceding the Glacial 
 epoch, when the vegetation of the temperate zone flourished 
 about the north pole, there was land connection between 
 the continents, permitting the larger species of the Old World 
 to migrate to North America. At the same time the con- 
 ditions in North America were favorable to the tropical spe- 
 cies of animals which had developed and flourished in South 
 America. The refrigeration of the climate on the approach 
 of the Glacial period, and the advance of the ice from the 
 north, cut off retreat to the Old World species, and gradually 
 hemmed them in over the southem portion of the continent, 
 where ail forms of life were compelled to readjust themselves 
 to new conditions. The struggle for existence probably re- 
 sulted, first, in the extinction of those South American spe- 
 cies which had invaded North America during the warmer 
 climate of later Tertiary times; and the more hardy emi- 
 grants from the north would have the advantage from the 
 similarity in climate in the southern United States during 
 the Glacial period to that about the poles, where they had 
 flourished immediately before. With the withdrawal of ice 
 to the north, the struggle of these animals with the condition 
 of existence began anew, and the mammoth and some others 
 found themselves unable to cope with the changes to which 
 they were compelled to adjust themselves. From the abun- 
 dance of remains of these animals found in the peat-bogs of 
 kettle-holes and in the glacial terraces of gravel and loess, it 
 is evident that they followed close upon the retreating ice- 
 front, and some of them continued the retreat to the Arctic 
 Circle, where they still hve and flourish ; while others, like 
 the elephant and mastodon, perished. 
 
 Few things are better calculated to impress the scientific 
 imagination than this dispersion and final extinction in North 
 America of so many large animals native to the Old World ; 
 
438 THE ICE AGE IN NORTH AMERICA. 
 
 while some of them, like the horse, were admirably adapted 
 to the present, conditions, as is shown by their rapid increase 
 since their introduction after the discovery of America by 
 the whites. In a succeeding chapter we shall also see that 
 man himself participated in this struggle with the new con- 
 ditions introduced by the Glacial period on this continent, 
 and that, in company with the mammoth, wah-us, and other 
 arctic species, he followed up the retreating ice both upon 
 the Atlantic coast and in the Mississippi Valley. Whether, 
 like some of his companions, he was unsuccessful in the con- 
 test is not certain, though there is much to be said in favor 
 of the theory that the Eskimos of the north are the lineal 
 descendants of the preglacial men whose implements are 
 found in New Jersey, Ohio, and Minnesota. Much also may 
 be said to support the theory, alluded to by Professor Clay- 
 pole, connecting the traditions of the destruction of large 
 portions of the human race by a flood with the extermination 
 of species naturally brought about by the conditions accom- 
 panying the floods which closed the Glacial period. 
 
 It is interesting to observe, also, that insects as well as 
 plants and the larger animals were compelled to reckon with 
 the Glacial period. They, too, participated in the southern 
 migration enforced by the advancing ice, and also shared in the 
 vicissitudes of its final retreat, compelling them to escape from 
 the warmer belt of cHmate which again advanced upon them 
 from the south. Like the forms of arctic and Alpine vegeta- 
 tion, a portion of the insects also took to the mountains, 
 where they still remain, as living witnesses to the reality of 
 the Glacial period. The summits of the White Mountains 
 are characterized by Alpine species of insects, one of which is 
 thus described by Mr. Samuel Scudder : 
 
 But even the narrow limit of the Alpine zone of the White 
 Mountains claims for its own a single butterfly, which probably 
 has a more restricted range than any other in the world. One 
 may search the season through over the comparatively vast and 
 almost equally barren elevations within the sub- Alpine district 
 of ihe White Mountains and fail to discover more than here 
 
FLIGHT OF PLANTS AND ANIMALS. 439 
 
 and there a solitary individual whirled by fierce blasts down 
 the mountain-slopes, while, a few hundred feet above, the but- 
 terflies swarm in great numbers. Every passage of the sun 
 from behind a cloud brings them out in scores, and they may 
 often be captured as fast as they can be properly secured. The 
 contrast between the occasional and unwilling visitor in the 
 sub-Alpine region and the swarms which flutter about the 
 upper plateaus is most significant. Yet the Garices, the food- 
 plant of the caterpillar, are quite as abundant in the lower 
 regions as in the upper, even to the species G. rigida, upon 
 which I found the larva feeding. Now, this butterfly {(Eneis 
 semidea) belongs to a genus which is peculiar to Alpine and 
 arctic regions ; in fact, it is the only genus of butterflies which 
 is exclusively conflned to them. It has numerous members, 
 both in this country and in the Old World. One is confined 
 to the Alps of Europe ; most of the European species, however, 
 are found only in the extreme north. The genus extends 
 across the whole continent of America, and several of its spe- 
 cies occur on the highest elevations of the Eocky Mountains. 
 Several species are common to Europe and America, and it is 
 to one of these that (Eneis semidea is most closely allied. A 
 few species descend into the Hudsonian fauna, but, as a whole, 
 the genus has its metropolis farther north. So that, in ascend- 
 ing Mount Washington, we pass, as it were, from New Hamp- 
 shire to northern Labrador ; on leaving the forests, we come 
 first upon animals recalling those of the northern shores of the 
 Gulf of St. Lawrence and the coast of Labrador opposite New- 
 foundland ; and, when we have attained the summit, we find 
 insects which represent the fauna of Atlantic Labrador and' the 
 southern extremity of Greenland.* 
 
 Commenting upon these and similar facts connected with 
 other species of butterflies and vnth several species of moths, 
 Mr. A. E. Grote pertinently says : f 
 
 The question comes up with regard to the White Mountain 
 butterfly, as to the manner in which this species of (Eneis 
 
 * "Geolosy of New Hampshire,'' toI. i, pp. 340, 341. 
 
 f "American Journal of Science," vol. ex, 18T5, pp. 337, 338. 
 
440 THE IGE AGE IN NORTH AMERICA. 
 
 attained its present restricted geographical area. . . . How 
 did the White Mountain butterfly get up the White Mount- 
 ains ? I am disposed to answer, by the action attendant on 
 the decline of the Glacial period. . . . 
 
 The main ice-sheet had pushed them insensibly before it, 
 and, during the continuance of the Glacial period, the geo- 
 graphical distribution of the genus (Eneis had been changed 
 from a high northern region to one which may well have in- 
 cluded portions of the Southern States. And, on its decline, 
 the ice-sheet drew them back again after itself by easy stages ; 
 yet not all of them. Some of these butterflies strayed by the 
 way, detained by the physical nature of the country, and 
 destined to plant colonies apart from their companions. When 
 the main ice-sheet left the foot of the White Mountains, on its 
 long march back to the pole, where it now seems to rest, some 
 of these wayward, flitting (Eneis butterflies were left behind. 
 These had strayed up behind the local glaciers on Mount 
 Washington, and so became separated from the main body of 
 their companions, which latter journeyed northward, follow- 
 ing the course of the retirement of the main ice-sheet. They 
 had found in eleration their congenial climate, and they have 
 followed this gradually to the top of the mountain, which they 
 have now attained, and from which they can not now retreat. 
 Far off in Labrador the descendants of their ancestral com- 
 panions fly over wide stretches of country, while they appear 
 to be in prison on the top of a mountain. I conceive that in this 
 way the mountains may generally have secured their Alpine 
 animals. The Glacial period can not be said strictly to have 
 expired. It exists even now for high levels above the sea, 
 while the Eskimos flnd it yet enduring in the far north. Had 
 other conditions been favorable, we might now find arctic 
 man living on snow-capped mountains within the temperate 
 zone. 
 
 At a height of from 5,600 to 6,200 feet above the level of 
 the sea, and a mean temperature of about 48° during a short 
 summer, the White Mountain butterflies {(Eneis semidea) yet 
 enjoy a climate like that of Labrador within the limits of New 
 Hampshire. And in the case of moths an analogous state of 
 things exists. The species Anarta melanopa isfoui .. on Mount 
 
FLIGHT OF PLANTS AND ANIMALS. 441 
 
 Washington, the Eocky Mountains, and in Labrador. Agrotis 
 Islandica is found in Iceland, Labrador, in the White Mount- 
 ains, and perhaps in Colorado. As on islands in the air, these 
 insects have been left by the retiring ice-flood during the open- 
 ing of the Quaternary. 
 
 On inferior elevations, as on Mount Katahdin, in Maine, 
 where we now find no (Eneis butterflies, these may formerly 
 have existed, succumbing to a climate gradually increasing in 
 warmth from which they had no escape ; while the original 
 colonization, in the several instances, must have always greatly 
 depended upon local topography. 
 
 In a Russian Government Report made in 1900, is found 
 a list of plants occurring in the provinces of Okhotsk and Kam- 
 chatka. This list contains 746 species of phaenogamous or 
 flowering plants, 173 identical species of which are common to 
 North America, that is, twenty-three per cent are found in 
 North America. Many of these species are distributed uni- 
 versally through the North Temperate Zone, and twenty-one 
 are known to have been introduced into America from Europe, 
 but have become naturalized. If now we compare the flora 
 of Manchuria, using the list published in the Russian Govern- 
 ment ReportonManchuriafor 1897, with that on Kamchatka 
 and Okhotsk for 1900, we find that there are 193 identical 
 species common to both, that is, nearly twenty-six per cent, 
 only five per cent more than that with North America. Of 
 the 173 species common to North America and the Provinces 
 of Okhotsk and Kamchatka, seventy-seven are also found 
 in Manchuria. Out of the 284 genera found in Okhotsk 
 and Kamchatka there are sixty-two genera not to be found 
 in North America. This number will probably be increased 
 when the Kamchatkan flora has been better studied, for the 
 region is so inaccessible that the lists at present must be 
 quite incomplete. 
 
 The following list gives the plants common to the Okhotsk- 
 Kamchatkan region and North America, those marked with 
 a (■*"> are common to Manchuria also. 
 
442 
 
 THE ICE AGE IN NORTH AMERICA. 
 
 Anemone pennsylvanica, L. 
 *A. nemorosa, L. 
 
 A. parviflora, Mich. 
 
 Ranunculus Flammula, L. 
 
 R. Cymbalarise, Purch. 
 *R. repens, L. 
 
 Caltha palustris, L. 
 
 Coptis trifolia, Salsb. 
 
 Actaea spicata, L. 
 
 Chelidonium majus, L. 
 
 Dicentra lachenaliaeflora, 
 Ldb. 
 
 Nasturcium palustre, Leyss. 
 *Barbarea vulgaris, R. Br. 
 
 Arabis hirsuta, Scop. 
 
 Cardamine bellidifolia, L. 
 
 C. pratensis, L. 
 
 Draba incana, L. 
 *D. nemorosa, L. 
 *Thlaspi arvense, L. 
 *Capsella Birsa pastoris, L. 
 *SisjTiibrium Sophia, L. 
 *Erysimumcheiranthoides, L. 
 
 Viola palustris, L. 
 
 V. blanda. Hook. 
 *V. canina, L. 
 
 Drosera rotundifolia, L. 
 *Stellaria media, Willd. 
 *S. borealis, MB. 
 
 S. himaifusa, Rot. 
 *S. longifolia, Muhl. 
 *S. longipes, Gold. 
 
 Cerastium vulgatum, L. 
 *C. arvense, L. 
 
 Linum perenne, L. 
 *Geranium sibiricum, L. 
 *Oxalis Acetosella, L. 
 
 Trifolium medium, L. 
 
 T. pratense, L. 
 
 Oxytropis campestris, D.C. 
 
 Astragalus alpinus, L. 
 *Vicia cracca, L. 
 *Lathyrus palustris, L. 
 
 L. pratensis, L. 
 *Spiraea betulifolia, L. 
 *S. salicifolia, L. 
 *Gum strictiun. Ait. 
 
 G. macrophyllum, Willd. 
 
 Potentilla norvegica, L. 
 
 P. Anserina, L. 
 *P. fruticosa, L. 
 *Fragaria vesca, L. 
 
 Pyrus sambucifolia, Cham. 
 et Schlect. 
 *Epilobium angustifolium, L. 
 
 Hippuris vulgaris, L. 
 
 Claytonia virginica, L. 
 
 Sedum Rhodiola, D.C. 
 *Ribes rubrum, L. 
 
 Saxifraga oppositifolia, L. 
 *Chrysosplenium altemifolia, 
 L. 
 
 Mitella nuda, L. 
 
 Ligusticum scoticimi, L. 
 
 Coelopleurum Gmelini, Ldb. 
 
 Carum carui, L. 
 
 Cornus canadensis, L 
 *Adoxa Moschatellina, L. 
 *Sambucus racemosa, L. 
 *Linnea borealis, L. 
 *Galium Aparine, L. 
 
 G. trifidum, L. 
 *G. varum. L. 
 *Erigeron acris, L. 
 
 Solidago Virgaurea, L. 
 
 *Achillea millefolium, L. 
 
FLIGHTS OF PLANTS AND ANIMALS. 
 
 443 
 
 A.'Ptarmica, L. 
 
 Matricaria discoidea, D.C. 
 
 Tanacetum vulgare, L. 
 
 Artemisia biennis, Willd. 
 
 A. Stelleriana, Bess. 
 *Gnaphalium ugliginosum, L. 
 *Senecio pseudo-Arnica, Less. 
 *Picris hieracioides, L. 
 *Taraxacum officinale, Wigg. 
 
 Crepis tectorum, L. 
 *Vaccinium Vitis-Idaea, L. 
 
 V. uliginosum, L. 
 
 Arctostaphylus alpina, Sprgl. 
 
 A. uva ursi, Sprgl. 
 
 Andromeda polifolia, L. 
 
 Phyllodoce taxifolia, Salsb. 
 
 Loiseuriaprocumbens, Desv. 
 *Ledimi palustre, L. 
 *Pyrola rotundifolia, L. 
 
 P. minor, L. 
 
 P. secunda, L. 
 *Moneses grandiflora, Salsb. 
 *UtricuIaria intermedia, 
 Hayne. 
 
 Primula farinosa, L. 
 *Lysimachia thyrsiflora, L. 
 
 Samolus Valerandi, L. 
 
 Gentiana Amarella. L. 
 *Menyanthes trifoliata, L. 
 *Polemonium coeruleum, L. 
 *Mertensia maritima, G. Don. 
 *Echinospermum Lappula, 
 
 Lehm. 
 *E. deflexum, Lehm. 
 
 Limostella aquatica, L. 
 
 Veronica Anagallis, L. 
 
 V. serpyllifolia, L. 
 
 Castelleja pallida, Kunt. 
 
 *Euphrasia officinalis, L. 
 *Mentha arvensis, L. 
 
 Thumus Serpyllum, L. 
 *Nepeta Glechoma, Benth. 
 
 Scutellaria galericulata, L. 
 
 Galeopsis Tetrahit, L. 
 *Plantago major, L. 
 *Rumex acetosa, L. 
 *Polygonum Bistorta, L. 
 *P. viviparimi, L. 
 *P. aviculare, L. 
 
 P. convolvolus, L. 
 
 Empertum nigrum, L. 
 
 Salix phylicifolia, L. 
 *S. myrtilloides, L. 
 *Populus tremula, L. 
 *P. alba, L. 
 
 *Humulus Lupulus, Ldb. 
 *Urtica dioica, L. 
 *Alnus incana, Willd. 
 
 Myrica Gale, L. 
 *Juniperus communis, L. 
 *Chenopodium album, L. 
 
 Atriplex patula, L. 
 
 Sparganium simplex, Huds. 
 
 Acorus calamus, L. 
 
 Zostera marina, L. 
 
 Potamogeton praelongus. 
 Wulf. 
 
 P. perfoliatus, L. 
 
 Triglochin palustris, L. 
 
 Alisma plantago, L. 
 
 Corallorhiza innata, R. Br. 
 *Microstylis monophylla, 
 . Lindl. 
 
 Calypso borealis, Salisb. 
 
 ""treptopus amplexifolius, 
 D.C. 
 
444 
 
 THE ICE AGE IN NORTH AMERICA. 
 
 Smilicina trifolia, Desv. 
 
 Allium Schoenoprasum, L. 
 *Veratrum viride, Ait. 
 
 Luzula spadicea. 
 *L. campestris, D.C. 
 
 Juncus balticus, Dethar. 
 
 J. filiform is, L. 
 
 J. articulatus, L. 
 
 Eriophorum vaginatum, L. 
 
 Carex alpina, Sw. 
 
 C. vulgaris, Fries. 
 *C. stenophylla, Wahl. 
 
 C. rariflora, Smit. 
 *Elymus mollis, Trin. 
 
 Festuca ovina, L. 
 
 Poa laxa, Henke. 
 *P. pratensis, L. 
 
 P. compressa, L. 
 
 P. serotina, Ehrh. 
 *P. nemoralis, L. 
 
 P. annua, L. 
 *Hierochloa borealis, R. et 
 
 Sch. 
 *Equisetum pratense, Chrk. 
 
 E. limosum, L. 
 *E. silvaticum, L. 
 
 E. variegatum, Sehleich. 
 
 E. scirpoides, Mich. 
 *E. arvense, L. 
 
 *E. hyemale, L. 
 
 Lycopodium Selago, L. 
 *L. annotinum, L. 
 *L. alpinum, L. 
 *L. complanatum, L. 
 *L. clavatiun, L. 
 
 Selaginella rupestris. Spring. 
 
 H. alpina, R. et. Sch. 
 
 Deschampsia caespitosa, P. 
 Bea. 
 
 Calamagrostis Langsdorffii, 
 Trin. 
 
 Agrostis canina, L. 
 
 Trisetum subspicatum, 
 
 Beanv. 
 *Phleum alpinum, L. 
 
 Cryptogamia 
 
 Botrychium Lunaria, Sw, 
 
 Polypodium vulgare, L. 
 *Woodsia ilvensis, R. Br. 
 
 W. glabella, R. Br. 
 
 Aspidum fragrans, Sw. 
 *Crystopteris fragilis, Bernh. 
 *Asplenium Folix-foemina, 
 
 Bernh. 
 *Pteris aquillina, L. 
 *Adianthum pedatum, L. 
 
 Struthiopteris germamca. 
 Willd. 
 
CHAPTEK XVIIL 
 
 EUROPE DUEING THE GLACIAI, PEEIOD. 
 
 At this point it will be profitable to take a survey of the 
 condition of some other parts of the world during the great 
 Ice age. By the same marks which determine the extent 
 of the glacier in America, it is evident that the existing gla- 
 ciers of Switzerland and Norway are but remnants of what 
 formerly existed in these localities. 
 
 James Geikie's statement of the situation in the British 
 Isles is sufficiently complete : 
 
 During the climax of the Glacial period all Scotland was 
 drowned in a wide-spread mer de glace, which coalesced in the 
 north and east with a similar sheet of ice, that crept outward 
 from Scandinavia. To the west the Scottish ice, meeting with 
 no impediment to its course, overflowed the outer Hebrides to 
 a height of 1,600 feet, and probably continued on its path into 
 the Atlantic as far as the edge of the 100-fathom plateau, where 
 the somewhat sudden deepening of the sea would allow it to 
 break off and send adrift whole argosies of icebergs. The 
 height reached by the upper surface of the ice that over- 
 whelmed the outer Hebrides enables us to ascertain the angle 
 of slope between those islands and the mainland. This was 
 1 in 211 — that is to say, the inclination of the surface of the 
 ice-sheet was about twenty-five feet in the mile — an inclination 
 which would appear to the eye almost like d dead level. . . . 
 
 The ice flowed off Ireland in all directions save to northeast 
 in Antrim, upon the coast of which it encountered the Scottish 
 mer de glace, which forced it to turn away to northwest and 
 southeast ; but along the whole western and southern shores, 
 
446 TEE ICE AGE IN NORTH AMERICA. 
 
 where no obstacle to its passage intervened, it seems to have 
 swept in one broad and continuous stream out — probably as 
 far as that of Scotland — into the Atlantic. The thickness 
 attained by the ice that flowed into the Irish Sea from Scot- 
 land, where it coalesced with the mer de glace coming from 
 the eastern seaboard of Ireland, and also, as we shall presently 
 see, with that creeping out from England and Wales, makes 
 it quite certain that the area now occupied by that sea must 
 at that time have been filled with glacier ice. . . . 
 
 The North Sea was filled with a massive iner de glace con- 
 tinually advancing in a general south-southwestern direction, 
 the presence of which is distinctly traceable in the remarkable 
 deflections of the glaciation all along the seaboard of Scotland 
 from Stonehaven southward. It was simply owing to the 
 superior elevation and extent of the Scottish mountains that 
 the narrow strip of low-lying ground in the eastern maritime 
 districts of that country was not invaded by an alien ice-stream. 
 When we pass into England the hills become lower, and the 
 area of low ground between the hills and the sea increases in 
 breadth. There was thus less and less opposition offered to 
 the southward advance of the North Sea mer de glace as it 
 pressed upon the eastern shores of England, until eventually 
 it overflowed bodily and crept southward across the midland 
 table-land on its way to the valley of the Severn and the Bristol 
 Channel. This remarkable glacial invasion is proved not only 
 by the carry of local stones, and stones which have come south 
 from the northern counties and Scotland, but by the appear- 
 ance in the till at Cornelian Bay and Holderness of bowlders 
 of two well-known Norwegian rocks, which were recognized 
 by Mr. Amund Helland. . . . 
 
 The ice which would thus appear to have streamed trans- 
 versely across England eventually coalesced with that which 
 overflowed from the basin of the Irish Sea southeast through 
 Cheshire, together with that which streamed east from the 
 Welsh uplands, and the united mer de glace thereafter made 
 its way into the Bristol Channel. Here it joined the thick 
 ice that flowed out to sea from the high grounds of South 
 Wales, the bottom-moraine of which is conspicuous not only 
 in the mountain- valleys of .that region, but also upon the low- 
 
EUROPE DURINa THE GLACIAL PERIOD. 447 
 
 lying tracts that extend from the hills to the sea. In the south- 
 eastern counties, so far as we know at present, the ice-sheet at 
 the climax of the Glacial period did not extend farther than 
 the valley of the Thames, beyond which no trace of its bottom- 
 moraine has been met with.* 
 
 Professor A. Geikie summarizes the facts concerning the 
 coptinent as follows : 
 
 In Scandinavia the ice-striae run westward and southwest- 
 ward on the Norwegian coasts, and eastward or southeastward 
 across the lower grounds of Sweden. When the ice descended 
 into the basin of the Baltic and the plains of northern Ger- 
 many, it moved southward and southwestward, but seems to 
 have slightly changed its direction in diiferent areas and at 
 different times. Its movements can be made out partly from 
 the striae on the solid rock, but more generally from the glacial 
 drift which it has left behind. Thus it can be shown to have 
 moved down the Baltic into the North Sea. At Berlin its 
 movement must have been from east to west. But at Leipsic, 
 as recently ascertained by Credner, it came from north-north- 
 west to south-southeast, being doubtless shed ofE in that direc- 
 tion by the high grounds of the Harz Mountains. Its southern 
 limit can be traced with tolerable clearness from Jevennaar, in 
 Holland, eastward across the Ehine Valley, along the base of 
 the Westphalian hills, round the projecting promontory of 
 the Harz, and then southward through Saxony to the roots of 
 the Erzgebirge. Passing next southeastward along the flanks 
 of the Eiesen and Sudeten chain, it sweeps across Poland into 
 Russia, circling round by Kiev, and northward by Nijni-Nov- 
 gorod toward the Urals. It has been estimated that, excluding 
 Finland, Scandinavia, and the British Isles, the ice must have 
 covered no less than 1,700,000 square kilometres of the present 
 lowlands of Europe. . . . 
 
 The ice is computed to have been at least between 6,000 
 and 7,000 feet thick in Norway, measured from the present 
 sea-level. From the height at which its transported debris 
 has been observed on the Harz, it is believed to have been at 
 
 ' Prehistoric Europe," pp. 189, 190, 192, 193. 
 
448 THE ICE AGE IN NORTH AMEBIOA. 
 
 least 1,470 feet thick there, and to have gradually risen in ele- 
 vation as one vast plateau, like that which at the present time 
 covers the interior of Greenland. Among the Alps it attained 
 almost incredible dimensions. The present snow-fields and 
 glaciers of these mountains,, large though they are, form no 
 more than the mere shrunken remnants of the great mantle of 
 snow and ice which then overspread Switzerland. In the 
 Bernese Oberland, for example, the valleys were filled to the 
 brim with ice, which, moving northward, crossed the great 
 plain, and actually overrode a part of the Jura Mountains, for 
 huge fragments of granite and other rocks from the central 
 chain of the Alps are found high on the slopes of that range 
 of heights.* 
 
 More recently the late Professor H. Carvill Lewis studied 
 the field in Great Britain, and published conclusions some- 
 what different from those which had been before accepted. 
 He traced, according to the summary giyen by Upham, a 
 terminal moraine "across southern Ireland from Tralee on 
 the west to the Wicklow Mountains and Bray Head southeast 
 of Dublin ; through the western, southern, and southeastern 
 portions of Wales ; northward by Manchester, and along the 
 Pennine Chain to the southeast edge of Westmoreland, thence 
 southeast to York, and again northward to the Tees, and 
 thence southeastward along the high coast of the North Sea 
 to Flamborough Head and the month of the Humber." f 
 
 Professor Lewis propounded the theory that the supposed 
 glacial deposits in England south of this line of terminal 
 moraine were to be explained as water- deposits in a glacial 
 lake produced by the damming up of the Humber Kiver and 
 a slight elevation of the earth at the Straits of Dover. It 
 is proper to say, also, that in this theory Professor Lewis had 
 been in part anticipated by Professor Boyd Dawldns, who 
 had written as follows : 
 
 The ice at this time was sufficiently thick to override 
 Schihallion, in Perthshire, at a height of 3,500 feet, and the 
 
 * " Text-Book of Geology," pp. 885, 886. 
 
 •j- " The American Geologist," vol. ii, 1888, p. STB. 
 
EUROPE DURING THE GLACIAL PERIOD. 449 
 
 hills of Gal way and Mayo at 2,000 feet. Its southern limit in 
 Britain is uncertain. According to Professor Eamsay and Dr. 
 James Geikie, it extended as far south as the latitude of Lon- 
 don , but the hypothesis upon which this southern extension 
 is founded — that the bowlder-clays haTe been formed by ice 
 melting on the land — is open to the objection that no similar 
 clays have been proved to have been so formed, either in the 
 arctic regions, where the ice-sheet has retreated, or in the dis- 
 tricts forsaken by the glaciers in the Alps or Pyrenees, or in 
 any other mountain-chain. Similar deposits, however, have 
 been met with in Davis Strait and in the North Atlantic, 
 which have been formed by melting icebergs ; and we may, 
 therefyre, conclude that the bowlder-clays have had a like 
 origin. . . . The English bowlder-clays, as a whole, differ 
 from the moraine profonde in their softness and the large area 
 which they cover. Strata of bowlder-clay at all comparable 
 to the great clay mantle covering the lower grounds of Britain 
 north of the Thames are conspicuous by their absence from 
 the glaciated regions of central Europe and the Pyrenees, which 
 were not depressed beneath the sea.* 
 
 Professor Lewis's views are of such interest that our treat- 
 ment of the subject would be incomplete without a fair pre- 
 sentation of them, which can best be done in his own words : 
 
 The great ice-sheet which once covered northern England 
 was found to be composed of a number of glaciers, each of 
 which was bounded by its own lateral and terminal moraines. 
 These glaciers were studied in detail, beginning with the east 
 of England ; and the North Sea Glacier, the Wensleydale Gla- 
 cier, the Stainmoor Glacier, the Aire Glacier, the Irish Sea 
 Glacier, and the separate Welsh glaciers were each found to 
 be distinguished by characteristic bowlders, and to be defined 
 by well-marked moraines. The terminal moraine of the North 
 Sea Glacier, filled with Norwegian bowlders, may be seen in 
 Holderness, extending from the mouth of the Humber to 
 Flamborough Head, and consists of a series of conical hills 
 inclosing meres. The moraine of the Stainmoor Glacier, char- 
 
 * "Early Man in Britain," pp. 116, 117. 
 
450 TEE ICE AGE IN NORTH AMERICA. 
 
 acterized by blocks of Shap granite, may be followed northward 
 along the coast past Scarborough and Whitby ; then west along 
 the Cleveland Hills ; then south again through Oulston to the 
 city of York ; then west to near Allerton, where the Stainmoor 
 Glacier is joined by the Wensleydale Glacier, a fine medial 
 moraine marking the line of junction. The Wensleydale Gla- 
 cier is characterized by bowlders of carboniferous limestone 
 and sandstone, and its lateral moraine is followed northward 
 through Wormald Green, Markington, Fountains Abbey, and 
 along the Permian outcrop to Masham, where it turns west to 
 Wensleydale, passing Jervaulx Abbey, and running up the val- 
 ley. North of Wensleydale the moraine of the Stainmoor Gla- 
 cier is followed through Kichmond to Kirby Eavensworth, and 
 westward to the mountains, where the glacier attained an eleva- 
 tion of two thousand feet. Thus the Stainmoor Glacier, a tongue 
 of the great Irish Sea Glacier, had been divided into two branches 
 by the Cleveland Hills, one branch going south to the city of 
 .York, which is built on its terminal moraine, the other branch 
 flowing out of the Tees, and being deflected southward along the 
 coast by the North Sea Glacier, with which it became confluent. 
 The Irish Sea Glacier, the most important glacier of Eng- 
 land, came down from Scotland, and being re-enforced by local 
 ice-streams, and flowing southward until it abutted against the 
 mountains of Wales, it was divided into two tongues, one of 
 which flowed to Wellington and Shrewsbury, while the other 
 went southwest across Anglesey into the Irish Sea. This great 
 glacier and its branches are all outlined by terminal moraines. 
 A small tongue from it, the Aire Glacier, was forced eastward 
 at Skipton and has its own distinctive moraine. In the neigh- 
 borhood of Manchester the great moraine of this Irish Sea Gla- 
 cier may be followed through Bacup, Hey, Stalybridge, Stock- 
 port, and Macclesfield, being as finely developed as the moraines 
 of Switzerland and America. South of Manchester, it contains 
 flint and shell fragments, brought by the glacier from the sea- 
 bottom over which it passed. At Manchester the ice was at least 
 fourteen hundred feet thick, beingas thick asthe Eh6ne Glacier.* 
 
 * Abstract by the author of a paper read at the Birmingham meeting of ths 
 British Association, September, 1886. 
 
EUROPE DURING THE GLACIAL PERIOD. 451 
 
 In a paper before the British Association in September, 
 1887, Professor Lewis presented his views in greater detail, 
 and answered objections, alleging that — 
 
 The hypothesis of extra-morainic fresh-water lakes, dammed 
 up by the glaciers, is sustained by all observed facts. The 
 most important of these lakes was one caused by the obstruc- 
 tion of the mouth of the Humber by the North Sea Glacier, 
 whose terminal moraine crosses that river at its mouth. This 
 large lake reached up to the 400-foot contour line, and ex- 
 tended southward nearly to London, and westward in finger- 
 like projections into the many valleys of the Pennine Chain! 
 It deposited the "great chalky bowlder-clay," and erratics 
 were floated in all directions by icebergs. It was bounded in 
 the vale of York by the Stainmoor Glacier, and Charnwood 
 Forest was an island in it. At its flood period it overflowed 
 southwestward ,by torrential streams into the Severn Valley 
 and elsewhere, carrying the "Northern Drift" into the south 
 of England. Other glaciers in England were bordered by simi- 
 lar but smaller lakes wherever they advanced against the drain- 
 age. Three such lakes were made by the Aire Glacier, the 
 largest of them extending to Bradford. The Irish Sea Glacier 
 caused many similar lakes high up on the west side of the 
 Pennine Chain, and at its southern end north of Wolverhamp- 
 ton. The overflow streams from the most southern of these 
 lakes joined those issuing from Lake Humber in the Birming- 
 ham district, characterized by a "commingling of the drift," 
 otherwise inexplicable. An examination of the supposed evi- 
 dences^ for glaciation, and for a great marine submergence in 
 central and southern England, shows that neither theory is 
 sustained by the facts. Thus, the supposed striae on Eowley 
 Rag prove to be root-marks or plow-marks ; those reported 
 at Charnwood Forest to be due to running water, or perhaps 
 icebergs ; the supposed drift on the chalk-wolds to be a local 
 wash of chalk-flints ; the high-level gravels on the Cotteswold 
 Hills to be preglacial ; the shells at Macclesfield, Moel Tryfan, 
 and Three Rock Mountain to be glacier-borne, and not a proof 
 of submergence ; the drift on the Pennine plateau of north 
 Derbyshire to be partly made by icebergs floating in Lake 
 
432 THE ICE AGE IN NORTH AMERICA. 
 
 Humber, and partly a decomposed millstone grit or Bunter 
 sandstone ; and the supposed Welsh erratics on Frankley Hill 
 at a height of eight hundred feet to be in place and due to an 
 outcrop of the palaeozoic floor. 
 
 The conclusion that the glacial phenomena of England are 
 due neither to a universal ice-cap nor to a marine submergence, 
 but to a number of glaciers bordered by temporary fresh-water 
 lakes, is in accordance with all the observations of the author 
 in England and elsewhere.* 
 
 It is fair to add, however, that soon after this meeting of 
 the British Association at which this paper was read, his 
 observations at Frankley Hill, in Worcestershire, and west- 
 ward, led Professor Lewis to waver in his views, and he had 
 resolved to go over all the ground again ; but his untimely 
 death prevented the accomplishment of this plan. Probably 
 there can be little doubt of the correctness of Mr. Upliam's 
 conclusion that, if Lewis had lived, he would have accepted 
 the opinions of the majority of the geologists of Great Brit- 
 ain, that land-ice really extended at one time as far south as 
 the Thames. " Still, small portions of northern England 
 escaped glaciation ; . . . and these tracts of the high moor- 
 lands in eastern Yorkshire and of the eastern flank of the 
 Pennine Chain are similar to the driftless area of southwest- 
 ern Wisconsin." It would seem from Professor Lewis's facts 
 about a moraine in England, as well as from those presently 
 to be stated concerning Professor Salisbury's discoveries in 
 northern Grermany, that the farthest extent of the ice-front is, 
 in Europe as well as in America, considerably in advance of the 
 well-defined terminal moraine, and suggests the same difference 
 of interpretation as here — i. e., this moraine is either the rem- 
 nant of a later glacial period or it is a moraine of retrocession. 
 
 * See also "American Journal of SciencS," vol. cxxxii, 1886, pp. 433-438; 
 "Proceedings of the Boston Society of Natural History," 1887; "Ueber Gla- 
 cialerscheinungen bei Gommern unweit Magdeburg" ("Zeltschr. d. Deutschen 
 geolog. Gesellschaft, Jabrg., 1883," pp. 831-848), and " Mittheilungen ueber 
 das Quartaer am Nordrande des Harzes" (ibid., " Jahrg., 1885," pp. 897-905), 
 VOD F. Wabnschaffe, in Berlin. 
 
EUROPE DDRMO THE GLACIAL PERIOD. 453 
 
 The conclusion of Professor Lewis concerning the marine 
 shells found at high elevations in glacial deposits on the 
 mountains of Wales, and which have generally been taken to 
 indicate a deep submergence during the Glacial epoch or at 
 the beginning of the second Glacial epoch, are of the greatest 
 importance, and coincide with similar discoveries recently 
 announced by Mr. Upham concerning the shells found in the 
 vicinity of Boston, and supposed to indicate a post-glacial sub- 
 sidence of considerable extent in that vicinity. These shells 
 in the British Isles, like those in the vicinity of Boston, are 
 mostly in fragments, are very thick and compact in structure, 
 and often water-worn and sometimes striated. Their eleva- 
 tion in the British Isles reaches as much as thirteen hundred 
 and fifty feet above tide. Professor Lewis thinks they 
 were plowed up by the glacier as it passed over the trough of 
 the Irish Sea, and were elevated to their present position by 
 the ice in the same manner that bowlders are seen so often to 
 have been elevated in various parts of the United States. I 
 again adopt the words of Mr. Upham in his recent comments 
 upon this theory : 
 
 The ample descriptions of the shelly drift of these and 
 other localities of high levels, and of the lowlands of Cheshire 
 and Lancashire, recorded by English geologists, agree per- 
 fectly with the explanation given by Lewis, which indeed had 
 been before suggested, so long ago as 1874, by Belt and Good- 
 child. This removes one of the most perplexing questions 
 which glacialists have encountered, for nowhere else in the 
 British Isles is there proof of any such submergence during or 
 since the Glacial period, the maximum known being five hun- 
 dred and ten feet, near Airdrie, in Lanarkshire, Scotland. 
 At the same time the submergence on the southern coast 
 of England was only from ten to sixty feet, while no traces 
 of raised beaches or of Pleistocene marine formations above 
 the present sea-level are found in the Orkney and Shetland 
 Islands,* 
 
 * " American Geologist," vol. ii, p. S76. 
 
454 THE ICE AGE IN NORTH AMERICA. 
 
 The work begun by Professor Lewis was subsequently car- 
 ried on by The Northwest of England Bowlder Committee, of 
 which Professor Percy F. Kendall was for some years the 
 efficient chairman. The final conclusion from these and other 
 investigations are thus briefly summarized by Dr. F. W. 
 Harmer,* as follows: 
 
 "Most glaciologists believe that this country was invaded 
 by ice, on the east from the German Ocean, and on the west 
 from the Irish Sea. Crossing the Lincolnshire Wolds, ice 
 from the North Sea, augmented, I think, by that of an 
 inland glacier from the Vale of York, traveled towards the 
 plain of the lower Witham and the Fenland, whence it over- 
 spread a large tract of country to the east, the south and 
 the west. To the east it reached the Suffolk coast, to the 
 south nearly to the valley of the Thames, while to the west 
 it filled those of the Welland, the Nene, and the Ouse, over- 
 riding also the highland intervening. 
 
 "Another branch of the northern glacier, keeping to the 
 west of the Lincoln ridge, and reinforced by the North-Sea 
 ice, moved towards Doncaster and up the Trent basin to 
 the vicinity of Derbe, where it met the Derwent glacier, and 
 thence crept southward along the valley of the Soar into 
 Warwickshire. 
 
 " On the west, the Cheshire plain was invaded by ice from 
 the Irish S3a which, diverting the glaciers descending from 
 the mountains of North Wales towards the south, carried 
 vast numbers of Scottish and Lake-District erratics into the 
 northern part of the basin of the lower Severn, heaping 
 them also upon Cannock Chase, and upon the high land near 
 Wolverhampton. 
 
 "In South Wales, Dr. Strahan and his colleagues have 
 shown that ice descended in great thickness from the Breck- 
 nock Beacons towards the Bristol Channel, reaching the 
 shores of the latter near Swansea, filling the Neath and Taff 
 valleys to overflowing, and rising to a great height on the 
 intervening hills. 
 
 *"Quarterly Journal of the Geological Society" for November 1907, 
 vol. Ixiii, p. 471-474. 
 
EUROPE DURING THE GLACIAL PERIOD. 455 
 
 "Evidence has also been found of the invasion of the 
 southern part of this district by ice from the Irish Sea, 
 which is supposed to have traveled up the Bristol Channel 
 from west to east, and to have crossed the Pembrokeshire 
 peninsula from St. David's Head towards Gower and to the 
 neighborhood of Cardiff: erratics believed to have been de- 
 rived from the first-named locality have been found nearly 
 100 miles to the eastward of their probable source. 
 
 "The depth of St. George's Channel between St. David's 
 Head and Ireland, however, exceeds 50 fathoms, and the 
 natural course of the Irish-Sea glacier, joined by those 
 descending the western slopes of the Welsh mountains, 
 should have been, southward along the great submarine 
 valley opening out to the Atlantic. The distribution of the 
 erratics just mentioned seems therefore to indicate that the 
 volume of ice, approaching the narrowest part of St. George's 
 Channel, was too great to enable it wholly to escape in that 
 direction, some of it being forced by lateral pressure to travel 
 eastward up the Bristol Channel. 
 
 "It seems worth considering whether so important an ice- 
 stream would not have blocked the entrance to the estuary 
 of the Severn, the result being an accumulation of sedentary 
 ice in the valley of that river, derived partly from the glaciers 
 of central Wales and partly from Atlantic blizzards, which 
 may have prevailed at that epoch. 
 
 "This view may possibly throw light on the origin of the 
 great alluvial and lake-like plain of Glastonbury, and of the 
 gorge at Clifton ... It may explain also why Arenig 
 boulders have been piled up on the Clent Hills, southwest 
 of Birmingham, to a height of nearly 900 feet. It is difficult 
 to understand that this could have occurred, if at that time 
 the Welsh ice could have followed an unobstructed course 
 along low ground towards the Bristol Channel. 
 
 "The conditions here sketched out, namely, of ice moving 
 upon central England from the sea in a direction opposed 
 to that of the natural drainage, are precisely those under 
 which glacial lakes with their accompanying over-flow chan- 
 nels would have naturally originnted." 
 
456 THE ICE AQE IN NORTH AMERICA. 
 
 During the summer of 1888 Professor Salisbury, who 
 had been for several years associated with President Cham- 
 berlin in the glacial survey of the Northwestern States and 
 Territories, made also a hasty survey of northern Germany 
 for the purpose of correlating the glacial deposits of that 
 country with those in America. The results were most im- 
 portant and interesting.* He found a double series of termi- 
 nal moraines back some distance from the extreme glaciated 
 limits, as in the Northwestern States of America, and resem- 
 bling them both in their composition and in their situation 
 with reference to the marginal deposits. As traced by Pro- 
 fessor SaHsbury, this belt of moraines follows approximately 
 the curve of the south shore of the Baltic Sea, and not many 
 miles from it. Its course lies through Schleswig-Holstein, 
 Mecklenburg, Potsdam (about forty miles north of Berlin), 
 thence swinging more to the north, and following nearly the 
 line between Pomerania and West Prussia, crossing the Vis- 
 tula about twenty miles south of Dantzic, thence easterly to 
 the Spirding See, near the boundary of Poland. 
 
 Among the places where this moraine can be best seen 
 are — " 1. In Province Holstein, the region about (especially 
 north of) Eutin ; 2. Province Mecklenburg, north of Crivitz, 
 and between Biitow and Kropelin ; 3. Province Brandenburg, 
 south of Eeckatel, between Strassen and Barenbusch, south 
 of Fiirstenberg and north of Everswalde, and between Pyritz 
 and Solden ; 4. Province Posen, east of Locknitz, and at 
 numerous points to the south, and especially about Falkenburg, 
 and between Lompelburg and Barwalde. This is one of the 
 best localities. 5. Province "West Preussen, east of Biitow ; 
 6. Province Ost Preussen, between Horn and Widikin." 
 
 Comparing these with the moraines of America, Professor 
 Salisbury remarks : 
 
 In its composition from several members, in its variety of 
 development, in its topographic relations, in its topography, in 
 
 * Professor R. D. Salisbury on " Terminal Moraines in Northern Germany," 
 in " American Journal of Science," vol. cxxxv, 1888, pp. 405, 406. 
 
458 
 
 THE IVE AGE IX SORTH AMERICA. 
 
 its constitution, in its associated deposits, and in its Avide sep- 
 aration from the outermost drift limit, this morainic belt cor- 
 responds to the extensive morainic belt of America, which 
 extends from Dakota to the Atlantic Ocean. That the one 
 formation corresponds to the other does not admit of doubt. 
 In all essential characteristics they are identical in character. 
 What may be their relations in time remains to be determined. 
 
 Fig. 124 — Contorteddnftof the rronierridffe; the terminal morn ino of the North Se:i ice. 
 
 The glaciated areas of the Pyrenees and the Alps are inde- 
 pendent of that covered by Scandanavian ice. In France, 
 small glaciers were to be found in the higher portions of the 
 Auvergne, of the Morvan, of the Vosges, and of the Cevennes; 
 while from the Pryenees, glaciers extended northward through- 
 out nearly their whole extent. The ice-stream descending 
 from the central mass of Mt. Maladetta through the uj^iier 
 valley of the Oaronne, was joined by several tributaries, and 
 attained a length of about forty-five miles. 
 
EUROPE DURING THE GLACIAL PERIOD. 459 
 
 The Alpine glaciers were much more extensive, filling the 
 whole valley between them and the Jura Mountains, and push- 
 ing up upon them to their summits. Eastward they deployed 
 in the valley of the Rhine as far as Strassburg, and westward 
 into the valley of the Rhone as far as Lyons, while southward 
 they extended nearly to Turin and Verona in the valley of the ■ 
 Po. The accompanying map of Professor Penck shows their 
 full extension eastward into Austria and the three successive 
 epochs which he names the Wiirm, the Riss, and the Mindel, 
 after the three-rivers in which the several deposits were most 
 typically preserved. These correspond to the Wisconsin, 
 the Illinoisan and the Kansan episodes in America, and were 
 readily recognized as such by Mr. Leverett. For its bearing 
 on later theorizing, it is worthy of notice that these several 
 borders are closely parallel to each other and not separated 
 by any great distance. 
 
CHAPTER XIX. 
 
 THE CAUSE OF THE GLACIAL PERIOD, 
 
 Foe the past few years speculation concerning the cause 
 of the Glacial period has been largely dominated by an 
 astronomical theory. But geologists have in general felt the 
 impropriety, in such an important matter, of abandoning 
 their own field to accept the glittering results of celestial 
 mathematics. At any rate, it would be improper for them 
 to let the astronomical solution go unchallenged. If the 
 geologist suffers himself to be lifted into the air, like the 
 fabled Antaeus, he labors at a disadvantage, and can be easily 
 overcome. For this reason the glacialists of America have, 
 of late, limited their labors chiefly to the collection of ter- 
 restrial facts, and when asked, as they often are, " What was 
 the cause of the Glacial period?" the first answer has fre- 
 quently been, " That is none of our business." Still, it is by 
 the interpretation of facts that causes are discovered, and the 
 collection of facts concerning the glaciation of North America 
 has advanced so rapidly during the past few years, that it is 
 now high time to consider more fully their meaning and 
 discuss the subject anew, if for no other reason than for the 
 sake of finding out how little is known about it. 
 
 It is easily seen that a glacier is the combined product of 
 cold and moisture. A simple lowering of the temperature 
 will not produce an ice age. Before an area can maintain a 
 glacier, it must first get the clouds to drop down a sufficient 
 amount of snow upon it. A climate which is cold and dry 
 mav not be so favorable to the production of glaciers as one 
 which is temperate, but whose climatic conditions are such 
 
462 THE ICE AGE IN NORTH AMERICA. 
 
 that there is a large snow-fall. For example, on the steppes 
 of Asia, and over the Eocky Mountain plateau of our Western 
 States and Territories, the average temperature is low enough 
 to permit the formation of extensive glaciers, but the snow- 
 fall is so Ught that even the short summers in high latitudes 
 cause it all to disappear ; whereas, on the southwestern coast 
 of South America, and in southeastern Alaska, where the 
 temperature is moderate, but the snow-fall is large, great 
 glaciers push down to the sea even in low latitudes. 
 
 The circumstances, then, pre-eminently favoring the pro- 
 duction of glaciers, are abundance of moisture in the atmos- 
 phere, and climatic conditions favorable to the precipitation 
 of this moisture as snow rather than as rain. Heavy rains 
 produce floods, which speedily transport the water to the 
 ocean-level ; but heavy snows lock up, as it were, the capital 
 upon dry land, where, like all other capital, it becomes con- 
 servative, and resists with great tenacity both the action of 
 gravity and of heat. Under the action of gravity glaciers 
 move, indeed, but they move very slowly. Under the influ- 
 ence of heat ice melts, but in melting it consumes an enor- 
 mous amount of force. 
 
 In order to melt one cubic foot of ice, as much heat is re- 
 quired as would heat a cubic foot of water from the freezing- 
 point to 176° Fahr., or two cubic feet to 88° Fahr. To melt a 
 layer of ice a foot thick will therefore use up as much heat as 
 would raise a layer of water two feet thick to the temperature 
 of 88° Fahr. ; and the effect becomes still more easily under- 
 stood if we estimate it as applied to air, for to melt a layer of 
 ice only one and a half inch thick would require as much heat 
 as would raise a stratum of air eight hundred feet thick from 
 the freezing-point to the tropical heat of 88° Fahr. We thus 
 obtain a good idea, both of the wonderful power of snow and 
 ice in keeping down temperature, and also the reason why it 
 takes so long a time to melt away, and is able to go on accu- 
 mulating to such an extent as to become permanent. These 
 properties would, however, be of no avail if it were liquid, 
 like water ; hence it is the state of solidity and almost complete 
 
THE CAUSE OF THE GLACIAL PERIOD. 463 
 
 immobility of ice that enables it to produce by its accumula- 
 tion such extraordinary effects in physical geography and in 
 climate as we see in the glaciers of Switzerland, and the ice- 
 capped interior of Greenland.* 
 
 Theories respecting the causes of the glacial period alto- 
 gether number more than half a score, principal of which are 
 the following: 1. A decrease in the original heat of the planet; 
 2. The shifting of the polar axis; 3. A former period of 
 greater moisture in the atmosphere; 4. The depletion of 
 carbon dioxide in the atmosphere by chemical union and 
 oceanic absorption; 5. Variations in the temperature of 
 space; 6. Variations in the amount of heat radiated by the 
 sun; 7. The combined effect of the precession of the equinoxes 
 and of the changing eccentricity of the earth's orbit; 8. 
 Changes in the distribution of land and water; 9. Elevation 
 of the lands in northern Europe and America to a higher level 
 than that now occupied. 
 
 Though these causes cannot in all cases, and perhaps not in 
 any case, be supposed to act except in combination with one 
 another, it will be profitable to consider them separately. 
 
 If, according to the first theory, the Glacial period was 
 due to a decrease of the original heat of the planet, the period 
 should not have culminated in the past, but we should still 
 be looking 'for its culmination in the future; for both the 
 eartli and the sun are cooling off. We may, therefore, drop 
 out the first theory. 
 
 If, according to the second theory, the cause had been the 
 shifting of the earth's axis of rotation, we should not find, as 
 we now do, evidences that the warm climate which preceded 
 the Glacial period approached the poles along the present 
 circles of latitude ; but, as it is, we find that the temperate 
 flora which covered the arctic regions at the close of the 
 Tertiary period approached the pole not only in Greenland 
 and British America, but also in Spitzbergen and Nova 
 
 * Wallace's " Island Life," pp. 12'?, 128. 
 
464 TEE lOE AGE IN NORTH AMERIOA. 
 
 Zembla. We may, therefore, drop this second theory out of 
 consideration. 
 
 The third theory, so ably advocated by Professor Whitney, 
 thart the Ice age was the direct result of the excessive moisture 
 of earlier periods, and that the disappearance of glaciers is to 
 be accounted for by a general drying up of the earth, is ruled 
 out by the fact that there is evidence, among other things, 
 from the vast deposits of salt existing in numerous parts of 
 the world, that the work of desiccation has been going on in 
 some portions of the earth from the earliest geological ages. 
 For example, central New York is, at the present time, one 
 of the best-watered portions of the world ; but it is underlaid 
 by deposits of salt sixty or seventy feet in thickness, and these 
 extend under much of the area of Upper Canada and Michi- 
 gan. To produce this amount of salt there must have oc- 
 curred, during the Upper Silurian age, the drying up of an 
 inland sea over that region a mile in depth. We are com- 
 pelled, therefore, to regard the era of the saline group of 
 rocks, rather than the present, as the great age of desiccation. 
 Besides, moisture in the atmosphere is efficient as a glacial 
 cause only when it is precipitated as snow, and this must be 
 determined by general meteorological conditions. There is 
 probably moisture enough always in the air to produce an 
 ice age if the conditions can be combined to precipitate it in 
 the right form and at the right place to encourage the growth 
 of glaciers. 
 
 The fourth theory is that argued at great length by Profes- 
 sors Chamberlin and Salisbury ("Geology," vol. ii, 665, vol. iii, 
 432). According to this theory the presence of an excessive 
 amount of carbon dioxide in the atmosphere increases the 
 warmth of the earth's surface by reducing the radiation. 
 Therefore, whatever reduces the carbon dioxide in the envel- 
 oping atmosphere of the earth will reduce its superficial 
 temperature. It is well known that preceding the glacial 
 epochs of the permian and pliocene periods there was a great 
 extension of land areas on both continents accompanied by 
 the formation of great mountain systems. This greatly in- 
 
THE CAUSE OF THE GLACIAL PERIOD. 465 
 
 creased the absorption of carbonic dioxide from the atmos- 
 phere, through the growth of vegetable and animal life. 
 This is shown by the coal and lignite deposits, and by the 
 vast beds of limestone and other carbonates. Through this 
 means it is suggested, the temperature of the whole earth 
 was so lowered that glaciers began to form in the higher lati- 
 tudes and on the higher mountains. Coincident with this 
 general lowering of temperature the water of the ocean, 
 especially in the higher latitudes, would begin to absorb a 
 greater proportion of the carbon dioxide and carry it down. 
 
 The theory in full is much more complicated than this, 
 and loses its value largely from this fact. But the most 
 obvious objection to it is that the operation of the forces in- 
 volved must be so slow that it could not fit into the rapid 
 succession of events which crowded in upon one another 
 during the last glacial period, which was characterized by 
 numerous episodes of advance and recession of the ice-sheet 
 and all within a very limited period even as geologists reckon 
 time. 
 
 The fifth theory and the sixth naturally go together. 
 That there may be variations in the temperature of space is 
 entirely within the realm of possibility, and that the sun 
 may be a variable star is a statement which can not be proved 
 absolutely false. Indeed, the hypothesis that the heat of the 
 sun is kept up by a bombardment of meteoroids is defended 
 by eminent astronomers. In case this were true, a known 
 natural cause for the production of variability is certainly in 
 the field, since the cometary bodies, which are circulating 
 irregularly through space, are probably themselves but ganglia 
 of meteoroids which may readily get entangled within the 
 predominant sphere of the sun's attraction, and become a 
 means of increasing for a long period the amount of the sun's 
 heat. This theory can not be positively aflSrmed to be true ; 
 but, as long as it can not be disproved by astronomical con- 
 siderations, it reinains in the field to diminish the confidence 
 with which we support other hypotheses. 
 
466 
 
 THE ICE AGE IN NORTH AMERICA. 
 
 The seventh theory mentioned had in Mr. Croll and in Mr. 
 James Geikie most able and convincing advocates, and for 
 many years was generally accepted as suflSicient and satisfac- 
 tory. Briefly stated, the theory is this: 
 
 As is well known, the earth's orbit is not a circle, but an 
 ellipse, whose longer diameter at the present time exceeds 
 its shorter by about 3,000,000 miles. The sun is not in the 
 center, but is in one of the foci of the ellipse, which at the 
 present is about 1,500,000 miles outside of the center. As 
 matters are now situated, therefore, the earth on the 21st of 
 June (when it is said to be in aphelion) is 3,000,000 miles 
 farther from tlie sun than it is on the 21st of December 
 (when it is said to be in perihelion) ; that is, during the pres- 
 ent winters of the northern hemisphere we are 3,000,000 
 miles nearer the sun than we are during the summers. 
 
 Fio. 125.— Exaggerated view of the earth's nrbit, showing the effects of precession of the 
 eqainoxes. A, condition of things now ; B, as it will be 10,500 years from now. 
 
 But, if a line be drawn through the earth's orbit joining 
 tbe equinoxes — that is, the points passed through on the 20th 
 of March and the 22d of September — we shall find that the 
 winter is shorter than the summer. The period from the 
 20th of March to the 22d of September, which constitutes 
 the summer, is one hundred and eighty-six days, while that 
 
THE CAUSE OF THE GLACIAL PERIOD. 467 
 
 from September 22d to March 20th is only one hundred and 
 seventy-nine days, or seven days less. So that, while the 
 earth is farther away from the sun during the summer, and 
 receiving daily less heat, the additional seven days occupied 
 by that part of the journey makes ample compensation, and 
 the absolute amount of heat received during the longer time 
 exactly equals that received by the earth during the shorter 
 half of its journey. It will be observed, also, that when the 
 summer in the northern hemisphere occurs at aphelion, the 
 summer in the southern hemisphere occurs in perihelion, thus 
 exactly reversing the conditions. 
 
 Now it is claimed by Mr. Croll and others that when, in 
 either hemisphere, the winter is short and occurs in perihelion, 
 the climate of that hemisphere will be less favorable to the 
 production of glaciers than in the hemisphere where the 
 winter is long and in aphelion. Consequently, according to 
 their theory, the situation of the earth is now favorable to the 
 production of glaciers in the southern hemisphere, and un- 
 favorable to their production in the northern. This theory 
 is not based, however, on the idea that the hemisphere whose 
 winter is in aphelion receives less heat from the sun than the 
 other hemisphere during that season, but upon the supposition 
 that the greater period occupied by the sun in passing through 
 aphelion when the winter nights are long, gives more oppor- 
 tunity for the loss of heat during winter in that hemisphere 
 by radiation. 
 
 Now, if it be correct that a winter in aphelion is favorable 
 to glaciation, and a winter in perihelion unfavorable, then, 
 from the astronomical changes which transfer this condition 
 periodically from one hemisphere to another, we can reason 
 that the northern and southern hemispheres are alternately 
 subjected to conditions favorable to glaciation. For, through 
 what is called the " precession of the equinoxes," the periods 
 of aphelion and perihelion are exactly reversed in their rela- 
 tions to the two hemispheres every 10,500 years. The points 
 at which the equinoxes occur are slowly sHpping around, 
 making a revolution once in about 21,000 years; so tliat, 
 
468 THE ICE AGE IN NORTH AMERICA. 
 
 10,600 years from the present time, the winter in the north- 
 ern hemisphere will occur in aphelion instead of perihelion ; 
 and, if the supposition be correct concerning the influence of 
 this increased iength of the winter and distance of the earth 
 from the sun, the conditions would favor the return of a 
 glacial period 10,000 or 11,000 years hence, and would imply 
 that similar favorable conditions existed 10,000 or 11,000 
 years ago. According to this theory, also, there should have 
 been a succession of glacial periods every 21,000 years during 
 long ages past. 
 
 But there is still another periodicity in the movements of 
 the earth about the sun with which to combine the preced- 
 ing. The shape of the earth's orbit is not permanent, but 
 through the influence of the attraction of the planets upon it 
 is subject to periodic changes. In astronomical terms, the 
 " eccentricity " of the earth's orbit is subject to variations ; 
 that is, there are sometimes very much greater differences 
 than at present between the longer and the shorter diameters 
 of the earth's orbit. When this difference is greatest it 
 amounts to no less than 7,000,000 miles ; so that at certain 
 times the earth is 14,000,000 miles farther from the sun in 
 winter than in summer, and vice versa. At the time of 
 greatest eccentricity, also, the difference in length between 
 the summers and winters would amount to thirty-six days, 
 instead of seven or eight as now. 
 
 These periods of greatest eccentricity in the earth's orbit 
 during which, on Mr. CroU's theory, the conditions were ex- 
 tremely favorable for the production of glacial epochs, are 
 somewhat unevenly distributed. One of them culminated 
 200,000 years ago; another, Y50,000 ; another, 850,000; 
 another, 2,600,000 ; and another, 2,600,000. In the future 
 they will occur 600,000, 800,000, 900,000 hence. In the 
 present condition of the earth's orbit this supposed cause is 
 at its minimum. 
 
 Of the astronomical changes affecting the eccentricity of 
 the earth's orbit, we are cei-tain. But the value of Croll's 
 theory depends upon the correctness of the original assump- 
 
THE CAUSE OF THE GLACIAL PERIOD. 469 
 
 tioB, that when the winters occur in aphelion there will be a 
 great increase of snow-faU and a marked lowering of tem- 
 perature during the winter ; and that, during the summers, 
 heat would have less than its average influence in removing 
 the snows of the previous winter. As already remarked, 
 however, it should be noted that Mr. CroU's calculations 
 upon these two points do not rest upon any difference in the 
 estimate of the absolute amount of heat received during 
 these periods. But he assumes that an excessive amount of 
 heat would be lost from the earth by radiation during the long 
 winters in aphelion ; so that the effect from that cause, when 
 accumulated during a number of centuries, would be marked 
 by a noticeable increase in the glacial fields of the hemisphere 
 whose winter was in aphelion, and this would be connected 
 with the decrease of glaciers in the other hemisphere, whose 
 winters were correspondingly short and in perihelion. 
 
 Having got glaciation started in one hemisphere during 
 periods when the winters were in aphelion, Mr. Croll ad- 
 duces an additional cause to help on the refrigeration, in the 
 effect which this cause itself would have upon the winds and 
 the ocean-currents. He estimates that the heat conveyed by 
 the Gulf Stream into the Atlantic Ocean is equal to one 
 fifth of all the heat possessed by the waters of the North 
 Atlantic ; or to the heat received from the sun upon a mill- 
 ion and a half square miles at the equator, or two million 
 square miles in the temperate zone. " The stoppage of the 
 Gulf Stream would deprive the Atlantic of 11,4n9,&?>Q,(iQ0,- 
 000,000,000 foot-pounds of energy in the form of heat per 
 day." The cause of the Gulf Stream, therefore, becomes a 
 most important element in the problem. What is the force 
 driving onward this immense body of warm water, which he 
 estimates " to be equal to that of a stream fifty miles broad, 
 a thousand feet deep, flowing at the rate of four miles an 
 hour," and whose temperature as it emerges from the Straits 
 of Florida averages as high as 65° Fahr., twenty-five degrees 
 of which is eventually parted with to ameliorate the climate 
 of the North Atlantic ? 
 
470 
 
 THE WE AGE IN NORTH AMERICA. 
 
 With great cogency of reasoning, Mr. Croll shows that 
 the trade-winds are the predominant cause of the present 
 course of the Gulf Stream. After attempting to show the 
 failure of all other theories to account for ocean-currents, and 
 for the direction of the Gulf Stream in particular, Mr. CroU 
 calls attention to the general correspondence between the 
 direction' of the winds and that of the great currents of the 
 ocean, and shows how powerful this agency must be in giv- 
 ing motion to the surface of the water, and by constancy of 
 action, finally, to the lower strata of water. Now, from 
 some cause or other, at the present time the southeast trade- 
 winds are considerably stronger than the northeast. As a 
 result, the southeast trades sometimes extend as far as latitude 
 10° or 15° north of the equator ; while the northeast trades 
 rarely extend even as far south as the equator.* The geo- 
 
 FiG. 126.— Map showing; conrse of cnrrente in the Atlantic Ocean, b and b' are cnirents 
 •et in motion by opposite trade winds ; meeting they produce the equatorial current 
 which divides into c and c' continuing on as a and a' and e. 
 
 * CroU's " Climate and Time," p. TO. 
 
472 TEE IDE AGE IN NORTH AMERICA. 
 
 graphical position and contour of South America give special 
 significance to this cause in its relation to tlie Gulf Stream 
 and to all the regions dependent on it for warmth of climate. 
 Cape St. Koque,. the easternmost point of South America, 
 is only five degrees south of the equator, and is fifty degrees, 
 or three thousand miles, east of the longitude of Florida. 
 With the present relation of the trade-winds to each other, 
 this situation of the continent of South America is favorable 
 to the production of the Gulf Stream. For it is evident at 
 a glance that the movement of water caused in the South 
 Atlantic by the southeast trades will be at its maximum over 
 the tropical belt in the vicinity of Cape St. Koque, and that 
 the movement there will be in a general northwest direction. 
 Hence there is great significance in the present contour of 
 the continent, it being such that there is nothing to impede 
 the movement of water once begun by the trade-winds in a 
 northwest direction (at least, so much of it as is north of 
 Cape St. Eoque) ; but the current thus started must keep 
 on its way until it reaches the cul-de-sac formed by the Gulf 
 of Mexico, and from this there is no escape except through 
 the passage between the West India Islands and Florida. 
 Here we have a deep, strong current, produced by the same 
 hydrostatic law which propels the comparatively small stream 
 in the hydraulic ram. Or, to draw an illustration from a 
 grander spectacle, the movement is like that of the tides 
 when passing up through gradually restricted channels. In 
 such cases the thin onward movement of the tidal wave over 
 a wide space is translated into a narrow but deeper and more 
 powerful current up the gradually restricted channel into 
 which it is forced ; so that, whereas the general height of 
 the tidal wave is but two or three feet, it sometimes in re- 
 stricted channels, like the Bay of Fundy, rises to the height 
 of seventy feet, and the so-called " bore," characteristic of 
 many tidal rivers, like the Orinoco and the Amazon, becomes 
 the terror of navigators. Through such a translation of the 
 gentle but steady presGure of the southeast trades over the 
 wide area of the South Atlantic Ocean, the waters of the 
 
THE GAUSE OF THE GLACIAL PERIOD. 473 
 
 Gulf Stream are projected through the Straits of Florida with 
 a force sufficient to carry them across the Atlantic and to the 
 shores of Iceland and jforway. So far Mr. Croll's explica- 
 tion is certainly very plausible, and seems to proceed from 
 well-known physical principles, and is pretty generally ac- 
 cepted by scientiiic men. 
 
 This, however, is only the first step in his argument. 
 Another glance at the map will show that if from any cause 
 the relations of the trade-winds should be reversed, so that 
 the northeast trades should predominate over the southeast, 
 and extend some degrees south of the equator, then Cape St. 
 Koque would intercept the movement caused by the south- 
 east trades, and the warm water from the South Atlantic, 
 which is now forced into the Caribbean Sea, would all of it 
 do what part of it now does, namely, turn to the south, and, 
 after following for a while the southwestern trend of the 
 South American coast, would join the slow-moving whirlpool 
 of the South Atlantic, whose center is on -the parallel joining 
 Montevideo and Cape Colony. It will thus appear that, in 
 searching for the cause of the Gulf Stream, we arer ultimately 
 compelled to search for the cause of the present preponder- 
 ance of the southeast trades in the Atlantic Ocean. This 
 sends us backward upon a receding series of causes. 
 
 The southeast trades preponderate because the southern 
 hemisphere is cooler than the northern hemisphere, for wind 
 is but the movement of the cooler and therefore heavier at- 
 mosphere of one region toward a partial vacuum produced 
 by a superior degree of heat in another. This conclusion 
 pushes us back one step further to find the cause for the 
 present lower relative temperature of the southern hemi- 
 sphere, and here we strike what is probably a coincidence, 
 but which Mr. CroU and his followers have too readily ac- 
 cepted as a cause. Mr. CroU thinks he finds the cause of 
 the low temperature of the southern hemisphere in the pres- 
 ent prevalence there, in moderate degree, of the astronomical 
 conditions to which he has attributed the production of gla- 
 cial periods. The winters of the southern hemisphere now 
 
THE CAUSE OF THE GLACIAL PERIOD. 475 
 
 occur in aphelion — that is, when the earth is farthest away 
 from the sun, and are seven days longer than the summers. 
 While admitting that there is not as yet enough known about 
 the laws governing the absorption and retention of the sun's 
 heat upon the earth's surface to permit us to say with confi- 
 dence that the acknowledged glacial condition of the southern 
 hemisphere is not produced by the astronomical cause under 
 consideration, it must be added that we are also unable to 
 prove the inadequacy of other causes to produce the same 
 results. In assuming the reality of Mr. Croll's cause, w^e are 
 in danger of resting on a theoretical may be rather than on 
 well-established premises. At any rate, Woeikoff, in the 
 ablest review that has yet appeared upon the subject, thinks 
 the glaciation of the southern hemisphere may readily enough 
 be accounted for without the aid of Croll's theory, and snms 
 up the case thus : 
 
 The extent and depth of the oceans of the southern hemi- 
 sphere give a greater steadiness and force to the winds of that 
 hemisphere, and the difference is even more marked if we com- 
 pare the westerly winds of middle latitudes rather than the 
 trades, though also well seen in the latter. Now, land acts in 
 two ways on the trade-winds : it weakens them, first, by the 
 increase of friction. But this is not all. The trades, few 
 ocean regions excepted, are not strong winds ; they are impor- 
 tant on account of their extent and steadiness. The gradient 
 which causes them is small. Now, in such cases, land, even if 
 it is not a continent but only a cluster of small islands, has a 
 great influence on trade-winds in causing local gradients which 
 may have even an opposite direction to the general gradients, 
 thus causing different and even opposing winds. The land- 
 and sea-breezes and the monsoons are cases in point. Even 
 where the disturbances of the normal ocean gradients are not 
 large enough to cause monsoons, we see generally the trades 
 often er interrupted in summer, when they are weaker and when 
 local thunder-storms and rains are more frequent on land. 
 For the two reasons given, the trades of the southern hemi- 
 sphere must be more extensive and stronger than those of the 
 northern. 
 
476 THE ICE AOE IN NORTH AMERIOA. 
 
 The relatively small extent of sea in middle latitudes of the 
 northern hemisphere, in comparison with the southern, must 
 tend to warm the seas of the former, even if the quantity of 
 warm water from the tropical seas reaching them be equal. 
 Thus, generally in the middle latitudes the evaporation goes 
 on at a higher temperature from the seas of the northern than 
 the southern hemisphere. Now, this has a very great influ- 
 ence on the resulting precipitations ; when the evaporation 
 goes on at or near 33°, there is much more probability that the 
 resulting precipitation will be snow and not rain, even on low 
 lands ; the higher the temperature at which the evaporation 
 takes place, the greater must be the height at which snow can 
 fall, on account of cooling by expansion. 
 
 Not all cold seas are favorable to glaciation. If they are 
 surrounded by land on which the winters have a temperature 
 considerably below 32°, they will be covered with ice, and thus 
 evaporation will be checked just at the time when it is most 
 favorable to snow-fall. The ice of the seas will be covered 
 with snow, the temperature of the air over it may be very low, 
 but the snow-fall will not be great, and thus the conditions not 
 favorable to glaciation. Such is the condition of many seas of 
 the northern hemisphere, as the Arctic Ocean north of Siberia, 
 the Kara Sea, the bays and inlets north of the North American 
 Continent, the Sea of Okhotsk, etc., which are covered with ice 
 during many months. These conditions are favorable to cold 
 of many months' duration, but not to a large snow-fall and 
 the resulting glaciation. The observations made at many 
 points off the coasts of Siberia and the North American Archi- 
 pelago have shown that the snow-fall is exceedingly light. The 
 seas between 45° and 70° of southern latitude are deep and not 
 surrounded by land, and thus by far not so ice-bound, both on 
 account of the absence of very low temperatures favorable to 
 the formation of ice, and of the rupture of ice, when formed, 
 by winds and currents.* 
 
 Thus it is shown that the depth and relative extent of 
 the southern ocean furnish a sufficient cause for its present 
 glacial conditions. 
 
 * "American Journal of Science," vol. cxxxi, 1886, pp. 176, 176. 
 
TEE GAUBE OF THE GLACIAL PERIOD. 477 
 
 As already intimated, the weak point in Mr. Croll's the- 
 ory is the general state of uncertainty as to the laws regulat- 
 ing the absorption, retention, and distribution of the sun's 
 heat upon the earth. It is evident that the heat upon which 
 the earth is dependent is that of the sun ; since, as Professor 
 Newcomb has shown, the total amount of heat received from 
 the stars is probably not one-millionth part of that received 
 from the sun.* Now, as all admit that the annual amount 
 of heat received from the sun is not affected by changes 
 either in the eccentricity of the earth's orbit, or in the rela- 
 tion of the poles to that eccentricity, it is only the question 
 of the retention and distribution of heat with which we have 
 to do. And here we come to a most obscure realm of sci- 
 entiiic investigation, where ignorance is still profound. The 
 reason why the summit of a mountain is cold is not because 
 of lack of heat from the sun, but it arises rather from the 
 facility with which the heat is dissipated by radiation. On 
 the contrary, the reason why the atmosphere of a greenhouse 
 is warmer than that upon the outside is not because it receives 
 more heat, but because it retains more. The intenser heat- 
 rays of the sun readily penetrate the glass cover, while the 
 less intense rays of radiated heat from the earth are unable 
 to do so in return. It is weU known, also, that clouds pre- 
 vent a frost by checking the radiation from the surface of the 
 earth. The laws regulating the influence of the atmosphere 
 and the floating particles contained in it, over the retention 
 of the sun's heat in its lower strata, are as yet but little un- 
 derstood. There is here an almost unlimited field for inves- 
 tigation and discovery. 
 
 And this, as just remarked, is the weak point of Mr. 
 Croll's theory. Everything here depends upon the forces 
 which distribute the heat and moisture over the land-sur- 
 faces. It is by no means certain that, when the winters of 
 the northern hemisphere occur in aphelion, they will be 
 colder than now. Whether they would be so or not depends 
 
 * "American Journal of Science," vol. cxi, 1S16, p. 264; vol. cxxvii, 1884, 
 p. 22. 
 
478 THE IGE AGE m NORTH AMERICA. 
 
 upon the action of forces whose laws can not now be accurately 
 calculated. As Woeikoff goes on to show, there are some very 
 singular facts in the distribution of heat over the earth's sur- 
 face — proving that the equator is not so hot as theoretically 
 it ought to be, and that the arctic regions are not so cold ; and 
 this in places which could not be affected by oceanic currents. 
 For example, at Iquitos, on the Amazon, only three hundred 
 feet above tide, three degrees and a half south of the equator, 
 and more than a thousand miles from the Atlantic (so that 
 ocean-currents can not abstract the heat from its vicinity), 
 the mean yearly temperature is but 78° Fahr., while at 
 Verkhojansk, in northeast Siberia, which is 67° north of the 
 equator, and is situated where it is out of the reach of ocean- 
 currents, and where the conditions for the radiation of heat 
 are most favorable, and where, indeed, the winter is the 
 coldest on the globe (January averaging —56° Fahr.) the 
 mean yearly temperature is two degrees and a half above zero ; 
 so that the difference between the temperature upon the 
 equator and that at the coldest point on the sixty-seventh 
 parallel is only about 75° Fahr. ; whereas, if temperature were 
 in proportion to heat received from the sun, the difference 
 ought to be 172°. Again, the difference between the actual 
 January temperature on the fiftieth parallel and that upon 
 the sixtieth is but 20° Fahr., whereas, the quantity of solar 
 heat received on the fiftieth parallel during the month of 
 January is three times that received upon the sixtieth, and 
 the difference in temperature ought to be about 170° Fahr. 
 upon any known law in the case. 
 
 But to be quite sure to get beyond the influence of ocean- 
 currents, I will take the mean January temperature in the 
 strictly continental climate of eastern Siberia, under 120° east. 
 According to Ferrel's tables : 
 
 Under 50° north we have 0° Fahr. 
 
 Under 60° north we have —30° Fahr. 
 
 If the January temperature decreased from 50° to 60° north, 
 according to the hypothesis of Dr. CroU, it should be on the 
 60° north -155° Fahr. 
 
THE CAUSE OF THE GLACIAL PERIOD. 
 
 479 
 
 But to be quite sure of taking the most favorable case for 
 the hypothesis of Dr. CroU, I take the highest January tem- 
 perature on the 50° north in Parrel's tables, that is, that on 
 20° east =44° Fahr., and the coldest January temperature on 
 the 60° north, that is, that of 130° and 130° east,= —30° Fahr. 
 Yet in proportion to the quantity of heat received, the mean 
 temperature of January on 60° north should be —140° Fahr. 
 
 The following table gives the results of the three cases con- 
 sidered : 
 
 
 Mean tem- 
 perature 
 
 SU-N. 
 
 MEAN TEMPEBitUBK, 60° N. 
 
 nifference 
 
 
 On the hypothe- 
 sis of Dr. OrolL 
 
 Actual 
 
 Mean January temperature of 
 all meridians 
 
 21-3 
 0° 
 
 440 
 
 - 147-9 
 
 - 165-3 
 
 - 140-0 
 
 1-7 
 -30 
 
 -30 
 
 149-6 
 
 Ucan January temperature in 
 120° E. (east Siberia) 
 
 Mean January temperature of 
 warmest meridian 50° N., and 
 coldest meridian on 60° N 
 
 125-3 
 110-0* 
 
 These facts, and many others like them, make it evident 
 that we understand very little about the laws governing the 
 distribution of heat over the surface of the earth. Other 
 things besides ocean-currents are active in the matter, and 
 some of them must be far more potent than any cause which 
 we now clearly discern. "We quote again the words of the 
 same high authority : 
 
 How can we judge of the change of temperature resulting 
 from this or that distance from the sun, even if we knew accu- 
 rately the temperature of space, when we do not know the dia- 
 thermancy of the atmosphere under different conditions ? We 
 know only that it is exceedingly different, according to the 
 different quantities of carbonic acid and aqueous vapor con- 
 tained in it, and in a far higher degree, according to the ab- 
 sence or presence in different quantities of suspended liquid 
 and solid particles (clouds, dust, smoke, etc.). Thus, when 
 
 * Woeikoff in " American Journal of Sdenoe," vol. cxzxi, p. 166. 
 
480 THE IGE A OE IN NORTH AMERICA. 
 
 we do not know in how far the loss of heat is impeded, even an 
 accurate knowledge of the temperature of space would be of 
 small use in this matter. I will illustrate this by a homely 
 example. Take a room where the fire is extinguished and the 
 hearth or stove cold in the evening, and try to guess at the 
 temperature the room will have in the morning. If we follow 
 the method of Dr. Croll, we should inquire only about the out- 
 side temperature, and not about the thickness of the walls, the 
 windows, etc. I think that, taking the average construction 
 of Kussian, English, and Italian houses, if the inside tempera- 
 ture was in all three cases 60° in the evening, and the outside 
 temperature 30° in Russia, 32° in England, and 45° in Italy, 
 the morning temperature in the room would not be very differ- 
 ent, and probably even higher in the Eussian room, owing to 
 its thick walls, double windows, etc. . . . 
 
 Thus it is easy to see that the question how great will be 
 the temperature of the air at a given place, say in midwinter, 
 when the distance of the sun is greater or less than at present, 
 can not be answered, even approximatively, especially in the 
 exceedingly crude way it is put by Dr. Croll — that is, without 
 distinguishing high and low latitudes, continent and ocean, 
 etc. One thing is certain, that such a change will certainly 
 have a greater influence on the temperatures in the interior of 
 continents than on the oceans and their borders. The caloric 
 capacity of water is so great, and the mobility of its particles 
 so effectual in resisting a lowering of the surface temperature, 
 by the convection currents it causes, that I doubt very much 
 if, during a great eccentricity and winter in aphelion, the sur- 
 face temperature of the oceans can be lower in winter than 
 now ; the difference in the quantity of sun-heat is too small 
 and too short-continued to give an appreciable difference in 
 winter ; and, as in the year there is no difference in the quan- 
 tity of heat received by the waters, I think there will be no 
 difference in the temperature of the waters, and thus no influ- 
 ence of great eccentricity with winter in aphelion on the ocean 
 temperatures, and also no greater snow-fall than now. As to 
 the continents, I admit that, though we are unable to calculate 
 the rate of decrease of temperature of the winter months in these 
 conditions, there is no doubt that it will be appreciable, and be 
 
THE CAUSE OF THE QLAOIAL PERIOD. 481 
 
 (he greater the less a given place is under the influence of the 
 seas.* 
 
 We may test the theory still further by an appeal to geo- 
 logical facts. According to Mr. Croll, there must have been 
 a succession of glacial periods in the past, and it would seem 
 that numerous indications of such epochs, if they occurred, 
 mast exist in the successive geological strata. If siich indi- 
 cations are not found in requisite amount, the advocates of 
 Mr. CroU's theory are bound to give a satisfactory explana- 
 tion of the failure. 
 
 To a consideration of this evidence Mr. Croll devotes the 
 seventeenth and eighteenth chapters of his book on " Climate 
 and Time," and at the outset confesses that " the facts which 
 have been recorded as evidence in favor of the action of ice 
 in former geological epochs are very scanty indeed." To ac- 
 count for this deficiency of evidence, he adduces, firet, " the 
 imperfection of the geological records themselves ; and, sec- 
 ond, the little attention hitherto paid toward researches of 
 this kind." 
 
 Mr. CroU's presentation of the reasons, from the nature 
 of the case, why the evidence of glaciation in the earlier geo- 
 logical periods should be in large degree obliterated, is prob- 
 ably as strong as can be made. He argues that the present 
 land-surfaces in nearly all cases represent former ocean-beds, 
 hence sedimentary strata deposited during the Glacial age 
 must consist of the water-worn material which had been car- 
 ried out from glacial streams into the bordering seas and 
 oceans, so that the most distinct signs of glacial action which 
 we could expect to find in sedimentary strata would be de- 
 posits of pebbles, forming conglomerate rocks, and the occur- 
 rence in these conglomerates of occasional angular fragments, 
 such as could only be transported on ice. 
 
 Mr. Croll, also, very naturally, dwells upon the extent to 
 which the land-surfaces exposed between two geological 
 epochs must have suffered from denudation. Erosive agen- 
 
 * Woeikoff in " American Journal of Science," vol. cxxxi, pp. 169, 172. 
 
482 TEE ICE AQE IN NORTH AMERICA. 
 
 cies would operate in the ordinary way dnring the whole 
 period of elevation, the streams carrying down to the sea a 
 large amount of material every season. But when the period 
 of depression had proceeded so far as to bring the surface 
 below the level of the sea, Mr. CroU believes the action of 
 the waves would greatly hasten the operation, and would 
 thoroughly sort out and roll the pebbles, washing the liner 
 particles into deeper water. 
 
 A careful consideration of the forces in operation, how- 
 ever, does not seem wholly to justify this reasoning of Mr. 
 CroU. In the first place, there must have been at various 
 geological epochs, over the area now most studied, extensive 
 land exposures, continuing through a long period of time. 
 The Tertiary deposits contain many vegetable remains as 
 well as animal, showing the existence of land areas of no 
 small extent. The Carboniferous period reveals whole con- 
 tinents maintaining, over a large portion of their extent, an 
 elevation near the sea-level, in which there were continual 
 but slight oscillations, tending, however, on the whole to 
 subsidence. So that land-plants accumulated in sufficient 
 quantity to form the coal-beds — the periods of depression 
 being marked by sedimentary rocks formed by the consolida- 
 tion of the wash that was spread over the whole region dur- 
 ing the times of depression. 
 
 Now, it does not seem possible that a glaciated area so ex- 
 tensive as is that of North America, and so deeply covered 
 with glacial debris, could be so completely removed by or- 
 dinary denuding agencies that no more signs of it should 
 appear than are found of such phenomena in the earlier geo- 
 logical epochs ; for the till, or ground-moraine, is not readily 
 removed by the action of water, even where subjected to the 
 shore-waves of the ocean. The bowlders which are washed 
 out of it form a protecting barricade around the base of the 
 deposit, so that islands like those in Boston Harbor, com- 
 posed wholly of till, are as nearly proof against the waves as 
 are those of ordinary rocks. If there were in progress a sub- 
 sidence of the glaciated area of North America, instead of 
 
THE GAUSE OF THE GLACIAL PERIOD. 483 
 
 having the waves wash the glaciated surfaces away gradually 
 from the edges inward, we should iind merely an encroacL- 
 inent made here and there upon the border during a portion 
 of the subsidence, until, finally, when the waters covered the 
 whole, all but a very thin stratum of the upper portion would 
 be protected from further disturbance. Especially must the 
 till remain in the innumerable buried channels of the glaci- 
 ated region, and over the extensive protected northern slopes. 
 It is thus difficult to conceive how there should ever be any 
 such complete removal of the ground-moraine from the im- 
 mense glaciated area of North America as Mr. CroU sup- 
 poses to have occurred several times over in preceding gla- 
 cial epochs. 
 
 The facts supposed to prove, by direct evidence, the ex- 
 istence of glacial peribds in the various successive geological 
 epochs, can be briefly stated.* 
 
 Beginning with some of the oldest sedimentary strata. 
 Professor Archibald Geikie has discovered what he believes 
 to be unmistakable signs of glacial action in the north of 
 Scotland, in Sutherland shire, on rocks of Cambrian age — 
 that is, just below the base of the Silurian system. Here he 
 reports extensive surfaces of gneiss rock worn into the char- 
 acteristic " rounded bossy surface " of glaciated regions, and 
 this evidently runs under an extensive deposit of breccia of 
 glacial origin, made up of fragments eroded by ice at that 
 early period of glaciation.f Some of the fragments of this 
 overlying breccia are said to be from five to six feet long. 
 
 A second instance of early glaciation, mentioned by Pro- 
 fessor Ramsay, occurs in the south of Scotland, in Ayrshire 
 and "Wigtonshire, in the Lower Silurian formations of that 
 region. Here are extensive sedimentary rocks, containing 
 
 * On the whole, the best summary of the evidence upon this subject, and the 
 one to which we are mainly indebted for the facts here presented, was given by 
 Sir A. C. Ramsay, Director-General of the Geological Survey of the tJnited King- 
 dom, in his Presidential Address before the British Association of Swansea in 
 1880. (See "Nature," vol. xxii, p. 388 et seq.) 
 
 t See communication to " Nature," vol. xxii, pp. 400-403. 
 
484 THE IGE AGE IN NORTH AMERICA. 
 
 characteristic Lower Silurian fossils, in which are numerous 
 erratic blocks of gneiss and granite, some of them as many as 
 nine feet in length. Both Dr. Eamsay and Mr. James Geikie 
 believe that the nearest source from which these fragments 
 could come is one hundred miles or more to the north. Their 
 theory is that, in the early Silurian times, the region occu- 
 pied by the Hebrides and the adjoining coast of northern 
 Scotland consisted of an immense granitic mountain uplift, 
 down which glaciers descended to the sea, sending oli bowlder- 
 laden icebergs, which wandered to the vicinity of Ayrshii-e 
 and Wigtonshire, and there dropped their burdens. 
 
 In India, also, according to Dr. Ramsay, Medlicott and 
 Blanf ord describe " old slates supposed to be Silurian, con- 
 taining bowlders in great numbers," which these experienced 
 authorities believe to be of glacial origin. They also de- 
 scribe other very ancient transition beds which overlie rocks 
 "marked by distinct glacial striations." Again, Dr. Ramsay 
 describes bowlder-beds in the south of Scotland, on the Lam- 
 mermoor Hills, south of Dunbar, which " contain what seem 
 to be indistinctly ice-scratched stones." These beds lie "un- 
 conformably on Lower Silurian strata," and are now gener- 
 ally believed by the members of the Geological Survey of 
 Scotland to be of glacial origin. Dr. Ramsay goes on to say : 
 
 I know of no bowlder formations in the Carboniferous series, 
 but they are weU known as occurring on a large scale in the 
 Permian brecciated conglomerates, where they consist of peb- 
 bles and large blocks of stone, generally angular, imbedded in 
 a marly paste ; . . . the fragments have mostly traveled from 
 a distance, apparently from the borders of Wales, and some of 
 them are three feet in diameter. Some of the stones are as 
 well scratched as those found in modern moraines or in the 
 ordinary bowlder-clay of what is commonly called the Glacial 
 epoch. In 1855 the old idea was still not unprevalent that 
 during the Permian epoch, and for long after, the globe had 
 not yet cooled sufficiently to allow of the climates of the exter- 
 nal world being universally affected by the constant radiation 
 of heat from its interior. For a long time, however, this idea 
 
THE CAUSE OF THE OLAOIAL PERIOD. 485 
 
 has almost entirely vanished, and now, in Britain at all events, 
 it is little if at all attended to, and other glacial episodes in the 
 history of the world have continued to be brought forward and 
 are no longer looked upon as mere ill-judged conjectures. 
 
 The same kind of brecciated bowlder-beds that are found in 
 our Permian strata occur in the Rotheliegende of Germany, 
 which I have visited in several places, and I believe them to 
 have had a like glacial origin. 
 
 Mr. G. W. Stow, of the Orange Free State, has of late years 
 given most elaborate accounts of similar Permian bowlder-beds 
 in South Africa. There great masses of moraine matter not 
 only contain ice-scratched stones, but on the banks of rivers 
 where the Permian rock has been removed by aqueous denuda- 
 tion the underlying rocks, well rounded and mammillated, are 
 covered by deeply incised glacier grooves pointing in a. direction 
 which at length leads the observer to the pre-Permian mount- 
 ains whence the stones were derived that formed these ancient 
 moraines. 
 
 Messrs. Blanford and Medlicott have also given,, in "The 
 Geology of India," an account of bowlder-beds in what they 
 believe to be Permian strata, and which they compare with 
 those described by me in England many years before. There 
 the Talchir strata of the Gondwana group contain numerous 
 bowlders, many of them six feet in diameter, and in one in- 
 stance some of the blocks were found to be polished and striated, 
 and the underlying Vindhyan rocks were similarly marked. 
 The authors also correlate these glacial phenomena with those 
 found in similar deposits in South Africa, discovered and de- 
 scribed by Mr. Stow. 
 
 In the Olive group of the Salt range, described by the same 
 authors, there is a curious resemblance between a certain con- 
 glomerate " and that of the Talchir group of the Gondwana 
 system." This "Olive conglomerate" belongs to the Creta- 
 ceous series, and contains ice-transported erratic bowlders de- 
 rived from unknown rocks, one of which, a red granite, "is 
 polished and striated on three faces in so characteristic a man- 
 ner that very little doubt can exist of its having been trans- 
 ported by ice." One block of red granite at the Mayo salt- 
 mines of Khewra "is seven feet high and nineteen feet in cir- 
 
486 THE ICE AGE IN NORTH AMERICA. 
 
 cumference." In the "transition beds" of the same authors, 
 which are supposed to be of Upper Cretaceous age, there also 
 are bowlder-beds with erratic blocks of great size. 
 
 I know of no evidence of glacial phenomena in Eocene strata 
 excepting the occurrence of huge masses of included gneiss in 
 the strata known as Flysch in Switzerland. On this question, 
 however, Swiss geologists are by no means agreed, and I attach 
 little or no importance to it as affording evidence of glacier ice. 
 
 Neither do I know of any Miocene glacier deposits except- 
 ing those 'in the north of Italy, near Turin, described by the 
 late eminent geologist,' Gastaldi, and which I saw under his 
 guidance. These contained many large erratic bowlders de- 
 rived from' the' distant Alps, which, in my opinion, were then 
 at least as lofty as or even higher than they are now, especially 
 if we consider the immense amount of denudation which they 
 underwent during Miocene, later Tertiary, and post-Tertiary 
 times.* > 
 
 In ITorth America Professor Shaler would attribute the 
 conglomerates of Jurassic age in the valley of the Con- 
 necticut, in a part of which lie the celebrated bird-tracks, to 
 glacial origin. This he infers, from the great thickness of 
 the beds, the absence of life from the accompanying sand- 
 stones, the subangular forms of many of the pebbles, and 
 from the similarity in composition of the pebbles of that 
 conglomerate with that of those found in the modern drift 
 of the region.f TTpon this conclusion, however, it is proper 
 to remark that the drift in the lower Connecticut Valley 
 would, to a great extent, come from the same region, whether 
 brought by ice or water, and the extent to which the pebbles 
 would have been reduced to uniformity and smoothness by 
 attrition depends upon the distance to which they have been 
 rolled, or the length of time to which they have been sub- 
 jected to wave-action. From what appears, the evidence is 
 not clear that the fragments from which the pebbles are 
 
 * "Nature," vol. xrii, p. 389. 
 
 f See " Illustrations of the Earth's Surface : Glaciers," by N. S. Shaler and 
 W. M. Davis. Boston: James R. Osgood & Co., 1881, p. 95. 
 
THE CAUSE OF THE GLACIAL PERIOD. 487 
 
 made may not have originated in the near vicinity, and so 
 their subangular condition need not imply glacial agency in 
 transportation. 
 
 Professor Shaler also is inclined to attribute the exten- 
 sive conglomerate deposits of the Carboniferous age in the 
 Appalachian district of North America to glacial action ; 
 and certainly the extent of these conglomerate deposits un- 
 derlying the coal-beds is surprising. " In Pennsylvania they 
 are about one thousand feet ; in eastern Kentucky and east 
 Tennessee their thickness rises to about two thousand feet." 
 Similar conglomerate deposits everywhere underlie the Car- 
 boniferous system. According to Professor Shaler, " we 
 find it from southern France to Scotland, from Alabama to 
 New Brunswick, in India, and elsevhere." For the most 
 part, however, the pebbles of this conglomerate consist of 
 quartz or quartzite, well rounded, and seldom of larger size 
 than can readily be transported by water ; though Professor 
 Newberry is reported to have "found a bowlder of quart.z- 
 ite seventeen inches by twelve inches, imbedded in a seam 
 of coal." Altogether it seems more likely that we have in 
 these conglomerates underlying the Appalachian coal-fields 
 of America the wash brought down by large rivers heading 
 in the mountain plateau toward the north and east, of which 
 the Archaean range on the Atlantic border, together with the 
 hills of New England and the Adirondacks of New York, are 
 but the remnants. That floating ice may have played some 
 part in the streams coming down from these mountain-heights 
 is not improbable ; but it is doubtful whether the facts war- 
 rant us in inferring anything more. 
 
 Professor Shaler would also attribute a still lower series 
 of conglomerates whose typical development is in eastern 
 Tennessee and western North Carolina, and which rests un- 
 conformably upon Laurentian rocks, to glacial action ; though 
 he confesses that no scratched bowlders have yet been dis- 
 covered in these deposits, but he writes : " Recollecting that 
 we know of no force that is competent to bring together such 
 masses of pebbles derived from a wide-spread surface save 
 
488 THE IGE AGE IN NORTH AMERICA. 
 
 glacial action, we are justified in believing that this deposit 
 is a prodiict of ice-action, though the waste has evidently 
 been worked over by water since its production." The 
 thickness of the deposits he estimates to be in some places 
 nearly twenty thousand feet. These deposits correspond in 
 age to the Koxbury conglomerates in Boston, which are 
 about five hundred feet in thickness, and " are composed of 
 materials derived from various points in eastern Massachusetts 
 and southern New Hampshire. The pebbles are rarely over 
 a foot in diameter." But Professor Shaler thinks "their 
 frequently subangular forms and the wide range of sub- 
 stances associated together make it pretty clear that they 
 have a glacial origin." 
 
 Upon this the same remark is applicable which was made 
 in a preceding section, namely, that along this whole Appala- 
 chian border there were formerly Archaean highlands of in- 
 definite height, of which the stumps are all that now remain 
 in the present hills and mountains. The erosion of these 
 mountains on their western flanks has furnished the material 
 of the vast sedimentary deposits of the eastern part of the 
 Mississippi basin. For all we know, the material spread out 
 over this area of sedimentary rocks was all within reach of 
 rivers coming down from Archaean heights, and so there is 
 no necessity of supposing extensive glacial transportation 
 from more northern water-sheds such as we are compelled to 
 suppose in the glacial age of recent date. The same remark 
 may be extended to all the evidence adduced in the preced- 
 ing sections concerning a succession of glacial periods.* In 
 all cases they are of such limited character that local glaciers 
 coming down from isolated mountain-masses, such as now 
 come down frym the mountains of Alaska, Patagonia, and at 
 no very distant date from those of iN^ew Zealand, are sufficient 
 to account for the facts. 
 
 Returning to the point under discussion, it is proper to 
 remark that the conclusions here presented with reference to 
 
 * See Lyell, " PrincipleB of Geology,'' vol. i, pp. 203-210. 
 
THE CAUSE OF THE GLACIAL PERIOD. 489 
 
 •Mr. Croll's theory are those pretty generally adopted at the 
 present time by the American geologists best qualified to in- 
 terpret the facts. Thus, among the more eminent American 
 geologists, Mr, G. K. Gilbert wrote, in 1883 : , 
 
 It deals with a series of physical laws and physical condi- 
 tions which interact upon each other in an exceedingly complex 
 way — in so complex a way that meteorologists, who have to 
 deal with only a portion of them, do not claim and scarcely 
 hope for a complete analysis of their combinations. The op- 
 portunities for arguing in a circle are most seductive, and the 
 a priori probability that important considerations have been 
 overlooked is not small. 
 
 The only manner in which so comprehensive and intricate 
 an hypothesis can be established is by stimulating inquiry which 
 shall lead to corroborative evidence, and this is precisely what 
 Croll's hypothesis, after eight years of wide publicity, has failed 
 to do. If it is true, then epochs of cold must have occurred 
 with considerable frequency through the entire period repre- 
 sented by the stratified rocks ; and iceberg drift, if no other 
 traces, should have been entombed at numerous horizons. It 
 has not been found, however, and of the eight horizons claimed 
 by CroU to show evidence of glacial action, the treatise under 
 consideration [A. Geikie's "Text-Book of Geology"] mentions 
 only two with confidence, and two others with doubt. In the 
 two instances to which queries are not attached, the phenomena 
 appear to indicate local and not general glaciation. If the 
 hypothesis is true, the cold of the Glacial epoch must have 
 been many times interrupted by intervals of exceptional warmth, 
 but little has been added to the evidence adduced by Groll for 
 such an interruption, and in America, where there is now great 
 activity in the investigation of glacial phenomena, the evidence 
 of a single inter-glacial period is cumulative and overwhelming, 
 while there is no indication whatever of more than one.* 
 
 With this agrees the opinion of President Chamberlin : 
 
 The various astronomical hypotheses seem to be the worse 
 for increased knowledge of the distribution of the ancient ice- 
 
 * " Nature," vol. xxvii, p. 262. 
 
490 THE ICE -AGE IN NORTH AMERICA. 
 
 sheet. I think I speak the growing conviction of active work- 
 ers in the American field, that even the ingenious theory of 
 CroU becomes increasingly unsatisfactory as the phenomena 
 are developed into fuller appreciation. I think I may say 
 this without prejudice, as one who, at a certain stage of study, 
 was greatly drawn toward that fascinating hypothesis. 
 
 But the more we know and ponder upon the enormous de- 
 velopment of ice upon the plains of northeastern America, and 
 contrast it with the relatively feeble development and disper- 
 sion from the mountainous regions of Alaska, which now bear 
 the greatest glaciers outside of the arctic regions, and the rela- 
 tive absence of such accumulations in northeastern Asia — ^in 
 short, the more we consider the asymmetry of the ice distri- 
 bution in latitude and longitude, and its disparity in eleva- 
 tion, the more difficult it becomes to explain the phenomena 
 upon any astronomical basis, correlated though it be with 
 oceanic and aerial currents and geographical features, by 
 whatsoever of ingenuity.* 
 
 Professor Le Conte remarks, in similar strain : 
 
 Of the recurrence of many glacial epochs in the history of 
 the earth there is as yet no reliable evidence, but much evidence 
 to the contrary. It is true that what seem to be glacial drifts, 
 with scored bowlders, etc., have been found on several geologi- 
 cal horizons, but these are usually in the vicinity of lofty 
 mountains, and are probably, therefore, evidence of local glacia- 
 tion, not of a glacial epoch. On the other hand, all the evi- 
 dence derived from fossils plainly indicates warm climates even 
 in polar regions during all geological periods until the Quater- 
 nary. The evidence at present, therefore, is overwhelmingly 
 in favor of the uniqueness of the Glacial epoch. This fact is 
 the great objection to CroU's theory, f 
 
 All doubts, concerning the existence of carboniferous and 
 Cambrian glacial periods have, however, been removed by 
 facts which have accumulated during the last twenty-five 
 
 *" Proceedings of the Aineric:in Association for the Advancement of Sci- 
 ence," vol. XXXV, p. 211. 
 
 t " Elements of Geology," p. 577. 
 
THE CAUSE OF THE GLACIAL PERIOD. 491 
 
 years. It is now well ascertained that there have been several 
 glacial periods but at irregular and widely separated intervals. 
 The irregularity of the intervals would indicate that the cause 
 cannot be the astronomical changes which Mr. CroU had 
 adduced, for they occur at regular intervals. The facts as 
 summarized by Professor Coleman are as follows:* 
 
 (1) The Huronian rocks of Canada, which are the oldest 
 sedimentary strata in existence, contain extensive conglom- 
 erates in every area mapped in northern Canada through a 
 region 1,000 miles long from east to west and 750 miles broad. 
 Some of the bowlders in this conglomerate are tons in weight, 
 while striated pebbles are as characteristic of glacial deposits 
 as can be found in any other age. Sir Archibald Geikie had 
 also noted similar deposits of archaean age in Scotland. The 
 deposits in Canada occur over hundreds of thousands of square 
 miles. 
 
 (2) In rocks of early Cambrian age extensive, conglom- 
 erates such as would be formed from the petrification of 
 glacial till are found in widely scattered regions, more specially 
 of the southern hemisphere. From such deposits. in China 
 Mr. Baily Willis has recently brought back beautifully 
 glaciated stones. But much larger areas in Australia and 
 South Africa are covered with "tillite" of Cambrian age. In 
 South Australia Mr. Howchin has traced these' deposits over 
 an area extending 450 miles from north to south s-nd 250 from 
 east to west, with a thickness of 1,500 feet. In South Africa 
 the Cambrian tillite has been traced by Mr.. Rogers oyer an 
 area of 1,000 miles. In both regions the glaciated area lies 
 near the 30th degree of latitude, andthemovement of bowlders 
 has apparently been from south towards the nortH..,i§in^ilar> 
 but less clearly defined Cambrian tillite has been^mpprtp^ at 
 various places about Lake Superior. In Australia thig^ ice 
 
 ♦"Glacial Periods and Their Bearing on the Geological Theories," 
 "Bulletin of the Geological Society of America," vol. xix, pp. 347-366. 
 
492 THE ICE AGE IN NORTH AMERICA. 
 
 movement evidently reached sea-level in regions which now 
 have a warm temperate climate. 
 
 There was a glacial epoch of great intensity at the close 
 of the carboniferous period, which has been studied with much 
 care in India, Australia, South Africa and South America. 
 In India bowlder conglomerates or "tillite" occur at points 
 which are from 700 to 800 miles apart, or if those reported 
 from Afghanistan be included, extending from latitude 35° 
 to 16°, a distance of 1,500 miles. In Australia this permo- 
 carboniferous tillite has been traced "widely in all the states 
 of the Commonwealth, including the island of Tasmania to 
 the south, with a range of latitude between 20° 30' and 43°. 
 Striated rock surfaces are often found under the old bowlder 
 clay, the directions of the scorings indicating a motion of the 
 ice in general from south to north, as might be expected; but 
 in various places the ice-sheet or sheets reached the sea, large 
 bowlders occurring in stratified shale, as if dropped from 
 ice, and marine fossils being found in close connection with 
 the beds containing bowlders." 
 
 The most remarkable glacial deposits of this age, however, 
 or in some respects of any age, are found in South Africa, 
 where fully 1,000,000 square miles are covered with tillite 
 extending from 30° southeast for a distance of 800 miles. It 
 is found in all the provinces "from the south of Cape Colony 
 to the middle of the Transvaal or possibly the southern boun- 
 dary of Rhodesia, and from Priesk, in Cape Colony, on the 
 west to eastern Natal." The deposit is thin in the north, and 
 thick in the south where, in Cape Colony, it reaches a thick- 
 ness of 1 ,000 feet. No striated rock surfaces are found in the 
 south, but they abound in the north. The deposits occur at 
 elevations of from 3,000 to 6,000 feet above the sea, but along 
 the southern margin the deposits were evidently laid down in 
 Water, whether salt or fresh has not been determined. The 
 most surprising thing about these deposits in South Africa is 
 thtit the transportation has been from the equator towards the 
 
Fig. 129— f;iaciatcd pebble, 7 iDclies lonE, from Fig. l:ill-C;iiniate(l pebble, 1 1 luehea 
 Lower Huronian, Cobalt, Pan. (A. P. Colman.) Ions, from Dwyka, Jlatjesfontein, 
 
 Cape Colony. (A. P. Colman.) 
 
 
 
 
 9 
 
 - " 'i?=??»si>(^rt!r^^^^ 
 
 
 nw^^'."' 
 
 
 
 
 • "^ ." 
 
 
 -"? 
 
 iffeS;- -: 
 
 'l*j 
 
 -^-"-.--■i?,S^5^,5,,gaK- : 
 
 -/-*:v-".:" V^ ■"■"' 
 
 
 
 ''-<^ 
 
 r 
 
 - '%'-<^ 
 
 ■\ 
 
 ■-\,;^'^'---:^ 
 
 Fro. 131 — Glaclate<l pleiHitocene surface from T>ower Huronian tllllte near Thessalon, 
 Ont. (A. P. Colman.) 
 
494 THE ICE AGE IN NORTH AMERICA. 
 
 south pole. This was indicated by the fact just mentioned 
 that they increased in thickness from north to south, as they 
 do in the pleistocene glacial deposits of North America, 
 though on different sides of the equator. But more decisive 
 evidence appears in the direction of the scratches on the under- 
 lying rock, which is from northwest to southeast; and from 
 the bowlders which have all been transported in the same 
 direction. 
 
 In India also the ice movement of the permo-carbonif- 
 erous period was from the equator northward, toward the 
 pole, in some cases bowlders having been transported 750 
 miles in that direction. 
 
 Other indications of a permo-carboniferous period have 
 been reported by Karpinsky and Tchernyschev in the Ural 
 Mountains, and by Ramsay in England, but no one has 
 discovered clear evidences of such deposits in America. 
 
 With reference to these deposits it is significantly remarked 
 by Professor Coleman that " as in the pleistocene, there seems 
 to have been an impressive grouping of the great ice-sheets 
 in a special quarter, this time in the neighborhood of Che 
 present Indian Ocean; and their nearness to the equator, on! 
 low ground and reaching to the sea, makes it all the more 
 puzzling that so little evidence of glacial work should be 
 found in higher latitudes." 
 
CHAPTER XIX. 
 
 THE CAUSE OF THE GLACIAL PERIOD — CONTINUED. 
 
 The eighth theory, which would attribute the growth and 
 disappearance of glaciers entirely to changes in the distribu- 
 tion of land and water over the surface of the globe, was, 
 according to his general principles, abiy and ardently advo- 
 cated by Sir Charles Lyell; and no one can read in his 
 "Principles of Geology" the chapters upon this subject 
 without being greatly impressed by the possible influences of 
 such changes. The ocean is the great equalizer of the earth's 
 temperature. Through unimpeded ocean-currents, like the 
 Gulf Stream of the Altantic and the Kuro-Siwa of the Pacific, 
 the heat of the tropics is transferred many thousands of miles 
 to ameliorate the climate of even the polar regions. It is 
 quite possible that comparatively slight changes in level in 
 the vicinity of the West India Islands and Central America 
 might so affect the direction of the Gulf Stream as to produce 
 most serious modifications of the climate in North America 
 and Europe. Should a portion of the Gulf Stream be driven 
 through a depression across the Isthmus of Panama into the 
 Pacific, and an equal portion be diverted from the Atlantic 
 coast of the United States by an elevation of the searbottom 
 between Florida and Cuba, the consequences would neces- 
 sarily be incalculably great, so that the mere existence of such 
 a possible cause for great changes in the distribution of moist- 
 ure over the northern hemisphere is suflicient to make one 
 hesitate before committing himself unreservedly to any other 
 theory — at any rate, to one which has not for itself indepen- 
 dent and adequate proof. 
 
496 THE ICE AGE IN NORTH AMERICA. 
 
 It is profitable, also, in this connection, to reflect on how 
 delicately balanced the forces of Nature now are with respect 
 to the production of glaciers. As already noted,* the gla- 
 ciers existing at the present time in the Alps have their peri- 
 ods of advance and recession. A slight increase in the 
 present snow-fall of Switzerland, if long continued, would 
 produce alarming results. From this cause alone, the 
 glaciers would at once begin to enlarge; and, in sympathy, 
 the temperature would fall, and the increase of the glaciated 
 area of Switzerland would go on until the whole country was 
 again brought under the desolating reign of ice, or until the 
 intervention of some counteracting force should stay its 
 advance. It is not without reason, therefore, that some 
 alarm was occasioned in Switzerland a few years ago by the 
 proposition to inundate the Desert of Sahara. Fortunately, 
 no extensive inundation of that region is within the reach of 
 human power. But, if it could be inundated, thus extend- 
 ing greatly the evaporating area from which the clouds 
 gather moisture for the Alpine heights, there is no telling 
 what the result might not be. Should there be an annual 
 increase of a foot of snow upon the Alps, a thousand addi- 
 tional feet of snow would have to be dissolved every thou- 
 sand years, with the enormous absorption of heat accom- 
 panying the process. This simple calculation is sufficient to 
 show the reality of the cause introduced by the eighth hy- 
 pothesis, which would explain the Glacial period through 
 the influence upon climate of changes in the distribution of 
 land and water. This cause is so effective that it may even 
 be conceived to be sufficient, without the introduction of any 
 other agencies. 
 
 The ninth theory, which introduces considerable change 
 of levels .n the continents, rests, without doubt, upon a true 
 cause, which, very likely, has cooperated with others, and 
 may in itself have been the chief agency in producing the 
 glacial conditions which we are studying. The evidence in 
 support of this theory was so well presented by Dr. Warren 
 
 *Seepagel05. 
 
THE CAUSE OF THE GLACIAL PERIOD. 497 
 
 Upham, in the appendix to the original edition of this volume 
 and his conclusions have been supported by so many lines of 
 evidence which have since come to light, that we now insert 
 it in the body of the discussion with such supplementary 
 notes as he has thought it necessary to add. It is a signifi- 
 cant confirmation of his views that Professor Chamberlin's 
 theory of the effect of the diminution of the carbonic dioxide 
 in the atmosphere in producing glacial conditions involves 
 extensive continental elevation of land surfaces as prelimi- 
 nary to the supposed depletion of this important element. 
 
 An examination of the evidence of changes in the relative 
 heights of land and sea in various parts of the world during 
 Quaternary time has led me to an explanation of the causes of 
 theGlacial period, which, in this application of its fundamental 
 principle, seems to be new, while in its secondary elements 
 it combines many of the features of the explanations proposed 
 by Lyell and Dana and by CroU. Briefly stated, the condi- 
 tion and relation of the earth's crust and interior appear to be 
 such that they produce, in connection with contraction of the 
 earth's mass, depressions and uplifts of extensive areas, some 
 of which have been raised to heights where their precipita- 
 tion of moisture throughout the year was almost wholly 
 snow, gradually forming thick ice-sheets; but under the heavy 
 load of ice subsidence ensued, with correlative uplift of other 
 portions of the earth's crust; so that glacial conditions may 
 have prevailed alternately in the northern and southern hemis- 
 pheres, or in North America and Europe, and may have been 
 repeated after warm interglacial epochs. 
 
 Quaternary oscillations of land and sea in glaciated regions 
 have been discussed by CroU and Geikie on the assumption 
 that the earth was so rigid that its form would not be changed 
 by the load of the ice-sheet nor by its removal, which seemed 
 more probable because of the well-known physical and mathe- 
 matical researches of, Hopkins, Thomson, Pratt, and Professor 
 G. H. Darwin, who conclude that the earth is probably solid, 
 
498 THE ICE AGE IN NORTH AMEBIGA. 
 
 with not less rigidity than that of glass or steel. In def- 
 erence to their researches, this conclusion is accepted and 
 taught in recent text-books of geology by Le Conte and A. 
 Geikie ; but in similarly recent text-books Dana and Prestwich 
 teach that the earth probably consists of a comparatively thin 
 crust underlaid by a molten interior, which may change within 
 a moderate depth to a great nucleal solid mass. Among other 
 geologists and physicists who have discussed the condition of 
 the earth's interior, King * and Shaler \ believe it to be solid ; 
 while Whitney,! Button,* Powell, || Wadsworth,^ Crosby, 
 Gilbert,! Claypole, % Airy, % Fisher,** and Jamieson,tt beheve 
 that it is molten, or, at least, is surrounded by a molten layer, 
 and that the earth's crust floats in a condition of hydrostatic 
 equilibrium upon the heavier liquid or viscous mobile interior 
 or layer enveloping the interior, subject, however, to strains 
 and resulting deformation because of the eai-th's contraction. 
 The thickness of the crust, according to this hypothesis, is 
 variously estimated to be from twenty to fifty miles, or possibly 
 a hundred miles or more. 
 
 It must be confessed that we have only a very inadequate 
 knowledge of the conditions which would result from the enor- 
 
 * "United States Geological Exploration of the Fortieth Parallel," vol. i, 
 "Systematic Geology," 1878, pp. 117,696-725. 
 
 f " Proceedings of the Boston Society of Natural History," 1866, vol. xi, pp. 
 8-15; 1868, vol. xii, pp. 128-136 ; 1874, vol. xvii, pp. 288-292. "Memoirs of 
 the Boston Society of Natural History," 1874, vol. ii, pp. 320-340. " Scribncr's 
 Magazine," vol. iii, pp. 201-226, February, 1888. 
 
 \ "Earthquakes, Volcanoes, and Mountain Building," 1871, pp. 77-87. 
 
 * "Penn Monthly," vol. vii, pp. 364-378, and 417-431, May and June, 1876. 
 " United States Geological Survey, Fourth Annual Report," pp. 183-198 ; "Sixth 
 Annual Report," pp. 196-198. 
 
 I "Science," vol. iii, pp. 480-482, April 18, 1884. 
 
 ^ " American Naturalist," vol. xviii, June, July, and August, 1884. 
 
 t) " Proceedings of the Boston Society of Natural History," 1883, vol. xxii, 
 pp. 443-486. "Geological Magazine," II, vol. x, 1883, pp. 241-252. 
 
 J " American Journal of Science," HI, vol. xxxi, pp. 284-299, April, 1886. 
 
 % " American Naturalist," vol. xix, pp. 257-268, March, 1886. " American 
 Geologist," vol. i, pp. 382-386, and vol. ii, pp. 28-35, June and July, 1888. 
 
 % " Nature," vol. xviii, pp. 41-44, May 9, 1878. 
 
 ** " Physics of the Earth's Crust," 1881, pp. 223, 270, etc. 
 
 +t " Geological Magazine," HI, vol. iv, 1887, pp. 844-348. 
 
THE CAUSE OF THE GLACIAL PERIOD. 499 
 
 mous pressure and high temperature of the earth's interior, and 
 wide diversity in speculations on this subject will probably long 
 continue. Professor Shaler, while holding that the earth is 
 mainly solid throughout, perhaps having in its most mobile 
 layer beneath the crust "a rigidity such as belongs to the 
 metals of average resistance to compression," yet is one of the 
 earliest and most decided advocates of the opinion that the 
 weight of an ice-sheet may depress the area on which it lies, 
 and that the departure of the ice would be attended by re- 
 elevation. In comparison, however, with the physical condi- 
 tions and laws familiar to us upon the earth's surface, the 
 subsidence and elevation of extensive areas, as of nearly all 
 glaciated regions, seem to demonstrate a mobility of the earth's 
 interior as if it were fused rock. The same conclusion is in- 
 dicated by volcanoes, which are probably the openings of molt- 
 en passages that communicate downward through the crust to 
 the heavier melted interior, thence deriving their supply of 
 heat, while their outpoured lavas consist largely or wholly of 
 fused portions of the crust, the phenomena of eruption being 
 caused by the access of water to the upper part of the molten 
 rock near the volcanic vent. But the great plications of the 
 strata in the formation of mountain-chains evidently involve 
 only the upper part of the earth's crust, crumpled into smaller 
 area in adapting itself to the diminishing volume of the lower 
 portion of the same crust, which, with the nucleus, is under- 
 going contraction on account of the gradual loss of its heat, 
 and perhaps also on account of progressing solidification and 
 compression. There is in this process no dependence on the 
 molten condition of the interior, except as that seems to be 
 necessary for distortion of the earth, both of the crust and 
 nucleus or mobile layer enveloping the nucleus, whereby con- 
 siderable shrinkage of volume can take place before the ac- 
 cumulated strain becomes sufficient for the formation of a 
 mountain-chain. At the present time depressions and eleva- 
 tions, prohably caused by accumulating strains, are slowly 
 changing the relations of land and sea upon many parts of the 
 earth's surface. In the same way the downward and upward 
 movements which would be caused by the burden of the ice- 
 sheet and its removal are doubtless in many places complicated 
 
500 TEE ICE AGE IN NORTH AMERICA. 
 
 by concomitant or subsequent movements thus due to defor- 
 mations under strains, by which the elevation attributable to 
 the departure of the ice-sheet m^y be augmented or partly or 
 wholly counteracted, giving much irregularity to the glacial 
 and post-glacial oscillations of the land. 
 
 Jamieson appears to have been the first, in 1865, to suggest 
 this view, which I receive from him, that the submergence of 
 glaciated lands when they were loaded with ice has been caused 
 directly by this load pressing down the earth's crust upon its 
 fused interior, and that the subsequent re-elevation was a 
 hydrostatic uplifting of the crust by underflow of the inner 
 mass when the ice was melted away.* Two years later Whit- 
 tlesey published a similar opinion. f In 1868 Shaler referred 
 the subsidence of ice-covered areas to a supposed rise of iso- 
 geothermal lines in the subjacent crust, operating, in conjunc- 
 tion with the ice-sheet, to produce downward flexure ; J but in 
 1874 and later he regards the depression as due directly to the 
 weight of the ice, and the re-elevation as due to its removal.* 
 The same view is advanced also by Chamberlin to account for 
 the basins of the Laurentian lakes, where he believes a con- 
 siderable part of the glacial depression to have been permanent. || 
 
 * " Quarterly Journal of the Geological Society," vol. xxi, p. 178. Later 
 discussions of this subject by Mr. Jamieson are in the '' Geological Magazine," 
 II, vol. ix, pp. 400-407 and 46T-466, September and October, 1882; and III, 
 vol. iv, pp. 344-348, August, 1887. In the article last cited, he applies this ex- 
 planation to the changes of the beaches of Lake Agassiz, which up to that time 
 I had attributed mainly to ice attraction. The same principle, however, was 
 brought forward by Herschel in 1836, and had been advocated by Professor 
 James Hall, of New York, in 1869, in attributing to the weight of sediments the 
 long continued subsidence of the areas on « hich they have been deposited in 
 great thickness. 
 
 t "Proceedings of the American Association for the Advancement of 
 Science," vol. xvi, pp. 92-97. 
 
 X " Proceedings of the Boston Society of Natural Histoiy," vol. xii, pp. 
 128-136. 
 
 * " Proceedings of the Boston Society of Natural History," vol. xvii, pp. 
 288-292; "Memoirs," ibid., vol. ii, pp. 336-340; "American Journal of 
 Sdence," III, vol. xxxiii, pp. 220, 221, March, 1887; " Scribner's Magazine," 
 vol. i, p. 259, March, 1887. 
 
 I " Geology of Wisconsin," vol. i, 1883, p. 290; " Proceedings of the Ameii- 
 can A'^sociation for the Advancement of Science," vol. xxxii, 1883, p> 212. The 
 
THE CAUSE OF THE GLACIAL PERIOD. 501 
 
 Accompanying the subsidence of ice-loaded areas, there were 
 doubtless uplifts of contiguous regions, perhaps sometimes in- 
 cluding outer portions of the country glaciated. For example, 
 the Quatenary elevation of which Le Conte finds evidence in 
 the Sierra Nevada and northward may have been contempora- 
 neous and correlative with depression of the northern parts of 
 the continent beneath its ice-sheet. Furthermore, instead of 
 being wholly offset by deformation of the crust, the glacial 
 depression may have produced also extensive extravasation of 
 lava, as is suggested by Jamieson * and Alexander Winchell,f 
 for the vast Quaternary lava-flows of California, Oregon, Wash- 
 ington, and a large adjacent region. As Jamieson well re- 
 marks, this result would tend to cause a permanence of part of 
 the depression of the ice-covered area. However it may have 
 been caused, probably such permanent Quaternary subsidence 
 is true for the coasts of many glaciated countries, as shown by 
 fiords, and for the basins of the Laurentian lakes, which, ex- 
 cepting Erie, are depressed several hundred feet below the level 
 of the ocean. 
 
 One of the most interesting fiords of North America is that 
 of the Saguenay, tributary to the St. Lawrence. Along a 
 distance of about fifty miles the Saguenay is from 300 to 840 
 feet deep below the sea-level ; its adjoining cliffs rise abruptly 
 in some places 1,500 feet above the water ; and the width of its 
 wonderfully sublime and picturesque gorge varies from about 
 a mile to one mile and a half. J This fiord, like the many 
 which indent our Eastern coast from Maine to Labrador and 
 Greenland, and our Western coast from Puget Sound to the 
 Arctic Ocean, was eroded by a stream that flowed along the 
 bottom of the gorge when it was above the sea ; and this erosion 
 was probably going forward in the epoch immediately preced- 
 
 problems of ice attraction and of deformation of the earth's crust have been 
 further discussed by President Chamberlin before the Philosophical Society of 
 Washington, March 13, 1886 ; and, jointly with Professor Salisbury, in the 
 " Sixth Annual Report, United States Geological Surcey," pp. 291-304. 
 
 * " Geological Magazine," II, vol. ix, 1882, p. 405. 
 
 f " American Geologist," vol. i, pp. 139-143, March, 1888. 
 
 t " J. W. Dawson, " Notes on the Post-Pliocene Geology of Canada," 1872, 
 p. 41. 
 
502 THE lOE AGE IN NORTH AMERICA. 
 
 ing the Ice age, for earlier subsidence during any period of 
 much length, geologically speaking, would hare caused the 
 submerged valley to be filled with sediments. The preglacial 
 elevation of the Saguenay region therefore appears to have been 
 at least 1,000 feet greater than now; and it seems to be similarly 
 proved by fiords that nearly the entire extent of the conti- 
 nental glaciated area was considerably higher before than after 
 glaciation. 
 
 There is also evidence that part of the Atlantic coast of the 
 United States close south of the limits of glaciation was at least 
 for a short time preceding the Glacial period uplifted much 
 above its present height. The submarine Hudson River fiord * 
 indicates that the vicinity of New York and Philadelphia then 
 stood 2,800 feet above the sea, and that it afterward slowly 
 sank 1,600 feet, while a bar of that height was formed by coast- 
 wise wash across the mouth of the fiord. In this remarkable 
 preglacial elevation, and in its being more or less shared by the 
 whole northern half of the continent, the formation of- the 
 North American ice-sheet seems to be explained. If this was 
 the cause of glaciation, probably the formerly greater height of 
 about 1,000 feet on the Saguenay was not exceptional. In- 
 deed, the elevation there and over large portions of the vast 
 territory of Canada, bounded on the east, north, and west by 
 fiord-indented coasts, may have been much more than is 
 measured by the depth of the Saguenay Eiver. 
 
 Going a step further back, we may regard this northward 
 elevation as a distortion of the earth's form in the storage of 
 energy of lateral pressure which culminated, with the introduc- 
 tion of the new factor of northward depression by the ice 
 weight, in the Quaternary uplifts of the Western plains, the 
 Eocky Mountains, the Sierra Nevada, and the Great Basin. 
 These important changes in the elevations of great areas during 
 the comparatively short Quaternary period seem to be consistent 
 only with the hypothesis that our globe has a comparatively 
 thin crust and a molten interior. 
 
 In the Glacial period significant changes of the sea-level 
 
 * A. Lindenkohl, " American Journal of Science," III, vol. xxii, pp. 476-480; 
 with plate, June, 1885. 
 
THE CAUSE OF THE GLACIAL PERIOD. 503 
 
 were caused : first, by abstraction of water from the ocean and 
 its deposition on the land as snow, which under pressure made 
 the vast ice-sheets ; and, second, by ice attraction of the ocean, 
 lowering it still further, except in the Ticinity of glaciated 
 lands. An area of about 4,000,000 square miles in North 
 America, and another of about 2,000,000 square miles in 
 Europe, were covered by ice-sheets, which in their maximum 
 extent had probably an average thickness of a half or two thirds 
 of a mile, or perhaps even of one mile. Assuming that these 
 ice-sheets were contemporaneous, but disregarding ice-fields of 
 smaller extent, which probably existed in parts of Asia and of 
 the southern hemisphere, as also the glaciers of mountain dis- 
 tricts, the lowering of the ocean surface, which covers approxi- 
 mately 145,000,000 square miles, would slightly exceed 100 
 feet, if the mean depth of the ice accumulation was half a mile. 
 More probably the sea over the whole globe was thus depressed 
 fully 150 feet, which would correspond to an average of about 
 3,600 feet of ice on the glaciated areas of North America and 
 Europe. For the second factor in causing such changes, Mr. 
 E. S. Woodward's computations* indicate that gravitation 
 toward the ice would further depress the ocean probably 
 twenty-five to seventy-five feet within the tropics and in the 
 southern hemisphere, while it would raise the level enough 
 near the borders of the ice-sheets to counterbalance approxi- 
 mately the depression due to the diminution of the ocean's 
 volume, and would lift portions of the North Atlantic and of 
 the Arctic Sea perhaps two or three hundred feet higher than 
 now. Stream erosion while the sea was lowered to supply the 
 ice of the Glacial period may explain the indentations of the 
 southeastern coast of the United States, as Pamlico and Albe- 
 marle Sounds, besides similar inlets in many other parts of the 
 world ; but the excavation of Chesapeake and Delaware Bays 
 seems more probably referable, at least in part, to the time of 
 preglacial elevation, with the channeling of the now sub- 
 merged Hudson fiord. 
 
 When the ice-sheet of the last Glacial epoch finally re- 
 
 * " United States Geological Survey, Sixth Annual Report," pp. 291-300 j 
 and " Bulletin No. 48," " On the Form and Position of the Sea-Level." 
 
504 THE lOE AGE IX NORTH AMERICA. 
 
 treated, the land which it had covered stood mostly lower 
 than now, as is shown by the occurrence of fossiliferous marine 
 deposits overlying the glacial drift up to considerable eleva^ 
 tions. Near Boston, and northeast to Cape Ann, the coast 
 seems to have been submerged to a slight depth, probably not 
 exceeding ten to twenty -five feet. Proceeding toward the 
 north and northwest, the elevation of the marine beds lying 
 on the glacial drift increases to about two hundred and twenty- 
 five feet iu Maine, about five hundred and twenty feet in the 
 St. Lawrence Valley at Montreal, and four hundred and forty 
 feet at a distance of one hundred and thirty miles west-south- 
 west of Montreal ; but eastward, along the St. Lawrence, it 
 decreases to three hundred and seventy-five feet opposite the 
 Saguenay, and does not exceed two hundred feet in the basin 
 of the Bay of Ghaleurs ; while these marine deposits are want- 
 ing in Nova Scotia and Cape Breton Island.* This subsidence 
 accords well with the explanation that it was due to the press- 
 ure of the ice -weight, which was greatest on the highlands 
 between the St. Lawrence and Hudson Bay. 
 
 Along the East Main coast of Hudson Bay and on Hudson 
 Strait raised beaches are conspicuous, according to Dr. Robert 
 Bell, up to heights of at least three hundred feet, f In the 
 region draining from the southwest to James Bay, Dr. Bell 
 reports marine shells in stratified beds overlying the glacial 
 drift along the Moose, Mattagami, and Missinaibi Rivers up 
 to about three huiidred feet above the sea ; \ along the Albany 
 
 * A. S. Packard, Jr., " Memoirs of the Boston Society of Natural History," 
 vol. i, pp. 281-262. J. W. Dawson, "Notes on the Post-Pliocene Geology of 
 Canada " ; and " American Journal of Science," III, vol. xxv, 1883, pp. 200-202. 
 C. H. Hitchcock, " Proceedings of American Association for the Advancement 
 of Science," Portland, 1873, vol. x.xii, pp. 169-176; "Geology of New Hamp- 
 shire," vol. iii, pp. 279-282 ; and " Geological Magazine," II, vol. vi, 1879, pp. 
 248-260. K. Chalmers, "Transactions of the Royal Society of Canada," sec. iv, 
 1886, pp. 139-146. W. Upham, "Proceedings of Boston Society of Natural 
 History," vol. xxiv, pp. 127-141, December, 1888; "American Journal of Sci- 
 ence," May, 1889. 
 
 t " Geological and Natural History Survey of Canada, Report of Progress 
 tor 1877-'78," p. 32 C; for 1882-'83-'84, p. 31 DD. 
 
 X " Geological and Natural History Survey of Canada, Report of Progresi 
 for 1 875-76," p. 340; for 1877-78, p. 7 C. 
 
THE CAUSE OF THE GLACIAL PERIOD. 505 
 
 and Kenogami Riyers up to a height of about four hundred and 
 fifty feet ; * and on the Attawapishkat to about five hundred 
 feet above the sea.f It is also evident that the shores of Hud- 
 son Bay are still undergoing elevation4 unlike the eastern coast 
 of the United States and Canada, where the post-glacial uplift- 
 ing has ceased, and there is now in progress a very slow sub- 
 sidence of the land from New Jersey to the Gulf of St. Law- 
 rence. 
 
 Scantier but yet conclusive proofs of the uplift of British 
 Columbia after glaciation are found in the valley of the Eraser 
 River, and on the Pacific coast, in Vancouver Island and the 
 Queen Charlotte Islands. Lamplugh has observed recent ma- 
 rine shells in a railway cutting on the west bank of the Harri- 
 son River, near its junction with the Fraser, at an elevation 
 not less than one hundred feet above the sea.* At New West- 
 minster, on the Fraser, near its mouth, raised beaches inclos- 
 ing fragments of marine shells are reported by Bauerman about 
 thirty feet above the river. || Fossiliferous marine deposits 
 found in the vicinity of Victoria and Nanaimo, in the south- 
 east part of Vancouver Island, at small elevations above the 
 sea, are believed by Dr. G. M. Dawson to have been formed at 
 or near the wasting edge of the ice-sheet ; ■^ and near the mid- 
 dle of the northeast side of this island two distinct deposits of 
 till occur, with intervening beds of loess-like silts, from which 
 
 * " Geological and Natural History Survey of Canada, Report of Progress 
 for 1871-"72," p. 112; for 1875-"76, p. 340; "Annual Report," vol. ii, for 
 1886, pp. 34 and 38 G. 
 
 f " Geological and Natural History Survey of Canada, Annual Report," vol, 
 ii, p. 27 G. 
 
 t " Geological and Natural History Survey of Canada, Report of Progress 
 for 18'77-"78," pp. 32 C and 25 CO; for 1S18-'19, p. 21 0; for 1882-'8S-'84, 
 pp. 26 and 30 DD ; " Annual Report," vol. i, for 1886, p. 11 DD. 
 
 * " Quarterly Journal of the Geological Society," vol. xlii, 1886, pp. 284, 286. 
 I " Geological and Natural History Survey of Canada, Report of Progress 
 
 eor 1882-'83-'84," p. 33 B. 
 
 ^ " Geological and Natural History Survey of Canada, Annual Report," vol. 
 ii, for 1886, p. 99 B ; " Quarterly Journal of Geological Society," vol. xxxiv, 
 1878, pp. 97, 98, and vol. xxxvii, 1881, p. 279. Compare also Mr. G. W. Lamp- 
 lugh's observations of glacial shell-beds at Esquimault, near Victoria, " Quar- 
 terly Journal of Geological Society," vol. xlii, 1886, pp. 276-284 
 
506 THE ICE AGE IN NORTH AMERICA. 
 
 this author infers two periods of glaciation, separated by an 
 interglacial epoch, in which the land was submerged from one 
 to two hundred feet.* Again, in the northeast part of the 
 Queen Charlotte Islands Dr. Dawson finds evidence of sub- 
 mergence to the amount of two or three hundred feet, while 
 the glacial conditions still endured, f 
 
 In Europe the glaciated area stood at a greater height be- 
 fore the Ice age, as is shown by fiords ; it was similarly de- 
 pressed while loaded with the ice-sheet ; and since then it has 
 been partially re-elevated. Its maximum post-glacial uplift 
 known in the British Isles, so far as it has not been counter- 
 acted by subsequent depression, is fire hundred and ten feet, 
 near Airdrie, in Lanarkshire, Scotland; % and in Scandinavia 
 it is about six hundred feet.* As in all the North American 
 districts noted, these upward movements seem attributable to 
 the rise of the earth's crust, upborne by inflow of a molten 
 magma beneath. 
 
 But the derivation of the floras of the Faroe Islands, Ice- 
 land, and even Greenland from the flora of Europe, demon- 
 strates, according to Professor James Geikie, that the portion 
 of the earth's crust extending from Britain and Scandinavia 
 to Greenland was uplifted in early post-glacial times about 
 
 * " Geological and Natural History Survey of Canada, Annual Report," vol. 
 ii, p. 105 B. 
 
 + " Geological and Natural History Survey of Canada, Report of Progress 
 for 1878-79," p. 95 B. Further important notes of recent changes in level of 
 the coast of British Columbia, and of Washington Territory and Alaska, are 
 given by Dr. Dawson in the " Canadian Naturalist," new series, vol. viii, pp. 241 
 -248, April, 1877. He concludes that this area had a preglacial elevation at 
 least about nine hundred feet above the present sea-level, during part or the 
 whole of the Pliocene period, this being indicated by the fiords ; that it was 
 much depressed in the Glacial period ; and that in post-glacial time it has been 
 re-elevated to a height probably two or three hundred feet greater than now, 
 followed by subsidence to the present level, the latest part of this oscillation 
 being a somewhat rapid depression of perhaps ten or fifteen feet during the 
 latter part of last century — a movement which may still be slowly going on. 
 
 X " Quarterly Journal of the Geological Society," vol. vi, 1860, pp. 386-388, 
 and vol. xxi, 1865, pp. 219-221 ; " American Geologist," vol. ii, pp. 371-379, 
 December, 1888. 
 
 *" Geological Magazine," I, vol. ix, 1872, p. 309; and II, vol. ii, 1876, 
 p. 390. 
 
THE CAUSE OF THE GLACIAL PERIOD. 507 
 
 three thousand feet higher than now ; * and the same author 
 shows that in interglacial time tropical animals passed from 
 Barbary into Spain upon land where now the Strait of Gi- 
 braltai- has a depth of one thousand feet.f These changes in 
 the relations of land and sea can not be ascribed to glacia- 
 tion, but seem to be distortions of the earth's form, such as 
 may be attributed to the action of strain upon the crust by 
 which the earth can become reduced in volume through the 
 subsidence and elevation of extensive areas during intervals 
 between epochs of mountain -building. In the same class of 
 changes are also to be included, wholly or in part, the post- 
 glacial elevation of Grinnell Land and the northwestern coast 
 of Greenland, one thousand to sixteen hundred feet ; J post- 
 Pliocene upward movements of two thousand feet or more in 
 Jamaica and Cuba ; * the recent uplift of the coast of Peru at 
 least twenty-nine hundred feet,|| which in diminished amount 
 seems to extend along the whole range of the Andes ; its prob- 
 able connection with the upheaval of the Cordilleras of North 
 America, where Le Conte believes that the elevatory move- 
 ments reached their greatest intensity in early Quaternary 
 time, causing a rise of several thousands of feet in the Sierra 
 Nevada ; ^ and the apparently correlative subsidence of a great 
 
 * " Prehistoric Europe," pp. 513-522, and 568, with Plate E. 
 
 f " Prehistoric Europe," pp. 325, 337-339 ; " Quarterly Journal of the Geo- 
 logical Society," vol. xxxiv, 1878, p. 505. 
 
 X " Quarterly Journal of Geological Society,'' vol. xxxiv, 1878, p. 66 ; " Geo- 
 logical Magazine," III, vol. i, 1884, p. 522. 
 
 * J. 6. Sawlfins, " Reports on the Geology of Jamaica," 1869, pp. 22, 23, 
 307, 311, 324-329; W. 0. Crosby, "On the Mountains of Eastern Cuba," " Ap- 
 palachia," vol. iii, pp. 129-142. Compare William M. Gabb's memoir, " On the 
 Topography and Geology of Santo Domingo," " Transactions of the American 
 Philosophical Society," vol. xv, pp. 103-111. 
 
 II A. Agassiz, " Proceedings of the American Academy of Arts and Sciences," 
 vol. xi, 1876, p. 287 ; and "Bulletin of the Museum of Comparative Zoology, at 
 Harvard College," vol. iii, pp. 287-290. Above this height, at which corals are 
 found attached to rocks, recent elevation of much greater amount seems to be 
 indicated by terraces, by saline deposits, and by the-presence of eight species of 
 AUorehestes — a genus of marine Crustacea, in Lake Titicaca, 12,500 feet above 
 the sea. 
 
 •^ "American Journal of Science," III, vol. xxxii, pp. 167-181, September, 
 1886. 
 
508 THE ICE AGE IN NORTH AMERICA. 
 
 area dotted with coral islands in the Pacific. The Quaternary 
 uplifts of the Andes and Rocky Mountains and of the West 
 Indies maise it nearly certain that the Isthmus of Panama has 
 been similarly elevated during the recent ept)ch. On the line 
 of the Panama Railway the highest land rises only two hundred 
 and ninety-nine feet above the sea, and the highest on the 
 Nicaragua Canal is about one hundred and thirty-three feet, 
 while the isthmus nowhere attains the height of one thousand 
 feet.* It may be true, therefore, that the submergence of this 
 isthmus was one of the causes of the Glacial period, the con- 
 tinuation of the equatorial oceanic current westward into the 
 Pacific having greatly diminished or wholly diverted the Gulf 
 Stream, which carries warmth from the tropics to the northern 
 Atlantic and northwestern Europe. 
 
 In view of the extensive recent oscillations of land and 
 sea both in glaciated and unglaciated .regions, it seems a rea- 
 sonable conclusion that, while some of these movements have 
 resulted directly from the accumulation and dissolution of ice- 
 sheets, more generally, when the whole area of the earth is 
 considered, they have been independent of glaciation. May 
 not such movements of the earth's crust, then, have elevated 
 large portions of continents, as the northern half of North 
 America and the northwestern part of Europe, to heights like 
 those of the present snow-line on mountain-ranges, until these 
 plateaus became deeply channeled by fiords and afterward cov- 
 ered by ice-sheets ? . For the recentuess of the latest glaciation, 
 believed to have ended in the northern United States not more 
 than ten thousand to six thousand years ago,f forbids our re- 
 
 * Charles Rlcketts, " The Cause of the Glacial Period, with reHerenoe to the 
 British Isles," "Geological Magazine," II, vol. ii, 1875, pp. 573-580. A. R. 
 Wallace, " The Geographical Distribution of Animals," vol. i, p. 40. 
 
 fN. H. Wiuchell, "Geology of Minnesota," "Fifth Annual Report," for 
 1876, and "Final Report," vol. ii, pp. 313-341; "Quarterly Journal of the 
 Geological Society," vol. xxxiv, 1878, pp. 886-901. E. Andrews, "Transactions 
 of the Chicago Academy of Sciences," vol. ii. James C. Southall, " The Epoch 
 of ihe Mammoth and the Apparition of Man upon the Earth," 1878, chaps, xxii 
 and xxiii. G. F. Wright, " American Journal of Science," III, vol. xxi, pp. 120- 
 123, February, 1881 ; " The Ice Ago in North America," chap. xx. G. K. Gil- 
 bert, "Proceedings of the American Association for the Advancement of Sci- 
 ence," vol. XXXV, 1886. 
 
THE CAUSE OF THE GLACIAL PERIOD. 509 
 
 ferring the glacial climate to conditions brought about by a 
 period of increased eccentricity of the earth's orbit from two 
 liundred and forty thousand to eighty thousand years ago, 
 which has been so ably maintained by CroU and Geikie ; and 
 some other adequate cause or causes must be sought for the 
 successive Quaternary glacial epochs of these great continental 
 areas and other districts of smaller extent both in the northern 
 and southern hemispheres ; also for the rare occurrence of gla- 
 cial conditions in various portions of the earth during past 
 geologic ages, especially in the Carboniferous and Permian 
 periods. The principal cause of all these epochs of glaciation 
 seems to the writer to be probably found by the clew supplied 
 in the relations already stated of the earth's crust and interior, 
 whereby they become somewhat distorted from the spheroidal 
 form while the process of contraction goes forward, the lateral 
 pressure bearing down some portions of the earth's surface, 
 and uplifting other extensive areas. Protuberant plateaus, 
 swept over by moisture-laden winds, would be the gathering- 
 grounds of vast ice-sheets, which would probably wax and 
 wane with the changes of the earth's attitude toward the sun, 
 by which the earth's place in any season, as summer, alternates 
 from aphelion to perihelion, and back to aphelion in cycles of 
 twenty-one thousand years. A similar explanation of the Gla- 
 cial period was long ago proposed by Lyell and Dana, but 
 without referring the elevatory movements to the earth's de- 
 formation by contraction and accumulating lateral pressure 
 while approaching an epoch of mountain -building, which 
 fundamental principle was first suggested to me in an article 
 from the pen of Professor W. 0. Crosby, on the origin and 
 relations of continents and ocean basins.* 
 
 During the periods immediately preceding great plications 
 and shortening of segments of the earth's crust involved in the 
 formation of lofty mountain-ranges, the broad crustal move- 
 ments causing glaciation would be most wide-spread and attain 
 their maximum vertical extent. The accumulation of ice- 
 sheets may have brought about the depression of their areas. 
 
 * "Proceedings of the Boston Society of Natural History," 1883, vol. xxii, 
 pp. 455-460. 
 
510 THE ICE AGE IN NORTH AMERICA. 
 
 with corresponding elevation of other plateaus, which in turn 
 would become ice-covered, so that the epochs of glaciation of 
 the northern and southern hemispheres may have alternated 
 with each otiier ; * and this may have been several times re- 
 peated, because of crustal oscillations due to ice- weight and its 
 removal, the effects of elevation and depression of the land 
 being re-enforced by climatic influences arising from the revolu- 
 tion each twenty-one thousand years in the place of the seasons. 
 When the building up of a great range of mountains ensued, 
 which may have been initiated and accelerated by the repeated 
 depressions under ice-weight and consequent transfers of the 
 earth's deformation from one region to another, the accumu- 
 lated strain in the earth's crust, with development of immense 
 lateral pressure, would be diminished below the limit of its 
 competency to cause glaciation. 
 
 Such Quaternary mountain-building is known to have oc- 
 curred on a most massive scale in Asia, where the Himalayas, 
 stretching fifteen hundred miles from east to west, and tower- 
 ing twenty thousand to twenty-nine thousand feet above the 
 sea, are known to have been formed, at least in great part, and 
 perhaps almost wholly, during this latest geologic period, f 
 contemporaneously with the glaciation of North America, 
 Europe, and portions of the southern hemisphere. Within the 
 same time the great table-land of Thibet, J and much of central 
 and northwestern Asia, have been uplifted ; the tract extend- 
 ing from the Black and Caspian Seas northeast to the Arctic 
 Ocean has risen to form a land-surface ; and the deep basin of 
 Lake Baikal has been probably formed in connection with 
 these crustal movements. Accompanying the formation of the 
 Himalayas, there has been doubtless much disturbance by 
 faults, local uplifts, and here and there plication of strata 
 
 * Compare the opinions of Hutton, cited in A. Geikie's " Text-Book of Geolo- 
 gy," second edition, p. 912, that the former greater extension of glaciers in New 
 Zealand was caused by an increase in the elevation of the land, and that it be- 
 longed to a much earlier time than the Ice age in the northern hemisphere, 
 probably to the Pliocene period. 
 
 t " Manual of the Geology of India," by H. B. Medlicott and W. T. Blanford, 
 Calcutta, 1879, Part I, pp. Ivi, 372; Part II, pp. 669-671, 667-669, 672-681. 
 
 X Ibid., Part II, pp. 5R6, 586, 669-674. 
 
THE CAUSE OF THE GLACIAL PERIOD. 511 
 
 along the whole complex east to northwest and west mountain 
 system of Oceania, Asia, Europe, and Northern Africa, from 
 JSIew^ Guinea, the Sunda Islands, Anam, and Siam, to the Cau- 
 casus, Carpathians, Balkans, Apennines, Alps, Pyrenees, and 
 Atlas Mountains, stretching quite across the eastern hemi- 
 sphere ; but the greater part of the relief from the previously 
 existing deformation of the earth was doubtless along the cen- 
 tral part of the belt, in the colossal Himalayan range. In 
 like manner the North American Cordilleras and the Andes, 
 reaching in one continuous mountain system from the Arctic 
 Circle to Cape Horn, have experienced within the same period 
 great disturbances, as already noted, similar to those of the 
 mountains of Southern Europe and the adjacent part of Africa. 
 With this American orographic belt is also probably to be 
 associated the mountain system, consisting largely of volcanoes 
 now active, which forms the Aleutian Islands, Kamtchatka, 
 the Kurile Islands, Japan, Formosa, the Philippines, Borneo, 
 and Celebes, lying nearly in the same great circle with the 
 Andes and Rocky Mountains, and with them continuous in 
 an arc of about two hundred and forty degrees. Along two 
 lines transverse to each other, one having an extent of half 
 and the other of two thirds of the earth's circumference, the 
 great lateral pressures of the earth's crust, which probably 
 caused the elevation and glaciation of extensive areas during 
 the Quaternary period, have been relieved by plication, faults, 
 and uplifts, in the processes of the formation of mountain- 
 ranges.* 
 
 Combined with oscillations of the earth's crust, which are 
 here regarded as the primary cause of the growth and decline 
 of ice -sheets, many other concomitant conditions, notably 
 changes in aerial and oceanic currents, and the earth's cycles of 
 twenty-one thousand years through precession and nutation, 
 enter into the complex causation of recurrent glacial and inter- 
 glacial epochs, and serve to intensify or to mitigate the severity 
 of the glaciation due to elevation. The influences of these 
 conditions would be nearly the same that are claimed for them 
 
 ,' I. * See Prestwich's "Geology," vol. i, chap, xvii, treating of the relatlre ages 
 of the principal mountain-ranges of the world. 
 
512 THE ICE AGE IN NORTH AMERICA. 
 
 in the luminous glacial theory of CroU, but their origin and 
 effectiveness toward causing a glacial climate are here referred 
 to extensive crust oscillations instead of eccentricity of the 
 earth's orbit. The prolonged warm interglacial epoch, or sev- 
 eral such epochs, of which evidence is obtained in the Qua- 
 ternary deposits of Europe and North America, preceded and 
 followed by severe arctic climate and ice-sheets, meet an ade- 
 quate and consistent explanation in the view hei'e taken ; and', 
 indeed, the same reasoning that is presented by Croll in thie 
 details of the secondary elements of his theory seems equally 
 applicable if these depend primarily on crustal elevation. ' 
 
 The principal interglacial epoch in the United States, un- 
 der this view, may well have been several times longer than 
 either the previous or subsequent epochs of glaciation, or than 
 the whole of post-glacial time, as claimed by McGee ; * but it 
 does not follow that an exact parallelism will be found in the 
 glacial history of Europe. Former extension of vast glaciers 
 in the Kocky Mountains and Andes, the Pyrenees and Alps, 
 the Atlas range, the Caucasus, the Himalayas, and elsewhere, 
 far exceeding the glaciers of the present time, may be due to 
 the uplift of these mountains much above their present height, 
 followed by subsidence \ with retreat of the ice ; but these os- 
 cillations and resulting alternations of climate were not proba- 
 bly synchronous everywhere. The highest mountain-ranges in 
 four grand divisions of the world — namely, Asia, Europe, and 
 North and South America — were doubtless largely uplifted and 
 plicated, with formation of deep adjoining lakes, during the 
 early part of the Quaternary period. Twice upheavals of the 
 whole district of the Alps seem to have covered the region with 
 great accumulations of ice, which each time may have depressed 
 the area, first to be succeeded by the formation of interglacial 
 deposits with lignite, and during each depression to send down 
 floods, spreading loess along the Khine, the Ehone, and the 
 Danube. J After the later epoch of subsidence and glacial re- 
 
 * "American Journal of Science," III, vol. xxxv, pp. 463-466, June, 1888. 
 f A. Geikie's "Text-Book of Geology," second edition, p. 9.<!4. 
 I J. Geikie's "Great Ice Age," second edition, cliapters xxxiii and xxxJT, 
 and his "Prehistoric Europe,'' chapters ix and xi. 
 
THE CAUSE OF THE GLACIAL PERIOD. 513 
 
 ccBsion, there seems to have been a renewal of elevation, as 
 shown by the height and slopes of the loess. 
 
 Asia had no extensive ice-sheet like those of Europe and 
 North America, probably because a sufficient elevation was not 
 attained there until the Himalayas and Thibet were uplifted in 
 the Glacial period. Their southern latitude and the position 
 of Thibet and Mongolia in an arid and partly rainless belt, 
 which stretches thence west to the Sahara, forbade their glacia- 
 tion ; but from these recently uplifted Asiatic table-lands and 
 mountains the most extensive Quaternary deposits of the world 
 have been brought down by rivers and spread in the vast low 
 plains of Siberia, eastern China, and northern India, sloping 
 gently toward the sea, into which the finer part of this allu- 
 vium is carried. All the puzzling features of the Chinese loess 
 formation,* reaching to great elevations with such thickness 
 and slopes of its surface that it could not be so accumulated as 
 alluvium of flooded streams under the present conditions, seem 
 to be readily explained by referring its deposition to annual 
 floods from immense snow-melting, during the European Grla^ 
 cial epochs, upon the gradually rising central part of the Asi- 
 atic Continent, which consists largely of easily erosible strata, 
 and had in pteglacial time become extensively disintegrated by 
 weathering under a dry climate. 
 
 With this reference of glaciation primarily to oscillations 
 of land, a new element of Quaternary history is introduced, 
 which seems to help much in accounting for peculiarities in 
 the areal distribution of identical or closely allied species of 
 animals and plants that have doubtless sprung from a common 
 source but have now become widely separated. Not only are 
 we able to follow Gray in his tracing the origin of the big trees 
 of California, of the species in the flora of the eastern United 
 States — which are the same with species of Japan, China, and 
 the Himalayan region, or are represented there by closely re- 
 lated forms, though unrepresented in Europe — and of mount- 
 
 * Baron Richthofen, " Geological Magazine," II, vol. ix, 1882, pp. 293-305. 
 J. D. Whitney, " American Naturalist," vol. xi, pp. '706-'?13, December, 187'?. 
 R. Pumpelly, " American Journal of Science," III, vol. xvii, pp. 133-144, Feb- 
 ruary, 1879. E. W. Hilgard, "American Journal of Science," III, vol. xviii, 
 pp. 106-112, August, 1879. 
 
514 TSE ICE AGE IN NORTE AMERICA. 
 
 ain plants identical with those of the Arctic zone ; * but also we 
 may now more satisfactorily bridge over the tropics and equa- 
 tor, by uplifts and subsidences of mountain-ranges, so that 
 species incapable of enduring a torrid climate could sometimes 
 become dispersed even to such distances as from north tem- 
 perate latitudes to Tierra del Fuego and the Cape of Good 
 Hope, f 
 
 It seems probable that the rate of the earth's contraction 
 has been somewhat uniform throughout the vast ages known 
 to us by the researches of geology ; but the corrugation of the 
 earth's surface in mountain-building has been much more rapid 
 in some epochs than in others, and between the times of for- 
 mation of great mountain-ranges there have been long intervals 
 of quietude. J The slowly progressing contraction of the globe 
 has been uninterrupted, and in some way the cooled outer part 
 of the crust which has not shared in this diminution of volume 
 has been able to accommodate itself to the shrinking inner 
 mass. As stated on a previous page, this has probably resulted 
 in distortion of the earth's form, both of the whole thickness 
 of the crust and of the probably molten interior, within mod- 
 erate limits during the periods of quiet, until so much lateral 
 pressure has been accumulated as to compress, fold, and uplift 
 the strata of a mountain-range. In attributing the severe 
 climate of glacial epochs to great uplifts of the areas glaciated 
 through such deformation preparatory to the process of mount- 
 ain-building, it is distinctly implied that the Quaternary period 
 has been at first exceptionally marked by such broad crustal 
 movements, and has since gained comparative rest from the 
 lateral stress to which they were due by equally exceptional 
 
 * " Sequoia and its History," " Proceedings of the American Association for 
 the Advancement of Science," Dubuque, toI. xxi, 1872, and " American Jour- 
 nal of Science,"' III, vol iv ; " Forest Geography and Archaeology," " American 
 Journal of Science," III, vol. xvi, 1878 ; " Characteristics of the North Ameri- 
 can Flora," " Report of the British Association for the Advancement of Science," 
 Montreal, 1884, and " American Journal of Science," III, vol. xxviii. 
 
 f Darwin's " Origin of Species," chapter xi. Wallace's " Geographical Dis- 
 tribution of Animals," chapter iii, and his " Island Life," chapter vii. 
 
 X Dana's " Manual of Geology," third edition, p. 796 ; Prestwich's " Geology," 
 vol. i, chap. xvii. 
 
THE CAUSE OF THE GLACIAL PERIOD. 515 
 
 plication, uplifts, and faults in the birth and growth of mount- 
 ains. Further, it is implied also that stress in the earth's crust 
 had been gradually increasing through long previous time, 
 while the processes of mountain-building failed to keep pace 
 with contraction, but were still sufficient to keep the earth's 
 deformation less than is required to produce glaciation ; for no 
 evidences of intense and widely extended glacial conditions are 
 found in the great series of Tertiary and Mesozoic formations, 
 representing the earth's history through probably ten or fifteen 
 millions of years. And indeed these conclusions, drawn from 
 the Quaternary Glacial period and the absence of glaciation 
 through vast eras preceding, accord well with the known age 
 and stages of growth of mountain-ranges that have been formed 
 during these eras. No epoch since the close of Palaeozoic time 
 has been more characterized by mountain-building than the 
 comparatively short Quaternary, whose duration may probably 
 be included within one hundred thousand or two hundred 
 thousand years. The continuation of the earth's faunas and 
 floi-as, with only very slight changes of species and exceedingly 
 rare instances of extinction through the Quaternary period, not- 
 withstanding its remarkable vicissitudes of climate and changes 
 in the relative heights of land and sea, which seem especially 
 adapted to produce both modifications and extinctions of or- 
 ganic forms, bears indisputable testimony of the brevity of this 
 period, when compared with those of Tertiary and Mesozoic 
 time. As we extend our investigations backward in the geo- 
 logic record, the species now existing are found in decreasing 
 numbers until we come to the beginning of the oldest. In 
 their places very different species, genera, orders, and groups 
 tenanted the earth before them ; and the gradual and doubtless 
 very slow evolution of the present from the past must have re- 
 quired duration almost incommensurable by years and centu- 
 ries. But the total of mountain-building that has taken place 
 during the Mesozoic and Tertiary eras is disproportionately 
 small in comparison with that of the Quaternary period, even 
 when ample allowance is made for long and very great denu- 
 dation. 
 
 Not until we go back to the Permian and Carboniferous 
 periods are numerous and widely distributed proofs of very 
 
516 THE ICE AGE IN NORTH AMERICA. 
 
 ancient glaciation encountered. The atmosphere had been 
 purified by the formation of Palaeozoic limestones of great 
 thickness, and by the storing up of the principal coal-deposits 
 of the world ; and these changes in the air had quite surely 
 produced greater diversities of climate than before existed, 
 especially in respect to the range of temperature in the seasons 
 and in the several zones. Alternating beds of coal, shales, and 
 sandstones, which form the coal-measures, indicate oscillations 
 of level and climatic conditions much like those of the Qua- 
 ternary period ; * and bowlder-bearing deposits, sometimes 
 closely resembling till and including striated stones, while the 
 underlying rock also occasionally bears glacial grooves and 
 striae, are found in the Carboniferous or more frequently the 
 Permian series in Britain, France, and Germany,! Natal,^ 
 India,* and southeastern Australia. | In Natal the striated 
 glacier floor is in latitude 30° south, and in India only 20° 
 north of the equator. During all the earth's history previous 
 to the Ice age, which constitutes its latest completed chapter, 
 no other such distinct evidences of general or interrupted and 
 alternating glaciation have been found ; and just then, in close 
 relationship with extensive and repeated oscillations of the 
 land, and with widely distant glacial deposits and striation, 
 we find a most remarkable epoch of mountain-building, sur- 
 passing any other time between the close of the Archaean era 
 and the Quaternary. The Appalachian Mountain system of 
 the United States, with its grand plications and upheaval of 
 the whole Palaeozoic group of rocks, belongs to this epoch, 
 and the same line of disturbance extends by faulting and up- 
 lifts northeastward to Gasp6 and Newfoundland. In Europe 
 
 * CroU's " Climate and Time," chap. xxvi. 
 
 f " Climate and Time," chap, xviii ; Wallace's " Island Life," chap. ii. 
 X "Quarterly Journal of the Geological Society," vol. xxvi, 1870, pp. 514- 
 B17; vol. xxvii, 1871, pp. 57-60. 
 
 * " Manual of the Geology of India," Part I, pp. xxxv-xxxviii, 102, 109-112, 
 229. 
 
 1 " Quarterly Journal of the Geological Society," vol. xliii, 1887, pp. 190- 
 196. " Die carbone Eiszeit," by Dr. W. Waagen, " Jahrbuch d. k. k. geol. Reich- 
 enstalt," Vienna, 1888, vol. xxxvii, Fait II, pp. 143-192; reviewed in the 
 "American Geologist," vol. ii, pp. 336-340, November, 1888. 
 
THE CAUSE OF THE GLACIAL PERIOD. 517 
 
 the Permian period ended with disturbance and mountain- 
 building along a somewhat irregular west-to-east course through 
 southern Ireland, "Wales, England, northern France, Belgium, 
 Germany, and southern Russia ; * and it is to be remarked 
 that this European orographic line lies approximately in the 
 same great circle with the Appalachian ranges, both being in- 
 cluded by an arc of ninety degrees. Transverse to this circle 
 the Sinian Mountain system of eastern Asia was formed in thfe 
 same epoch, stretching from southwest to northeast alofig tlie 
 border of the Old World as the Appalachians similarly bdiind 
 our own continent.! Each of these mountain systems was 
 perhaps much longer than the extent now remaining, and each 
 has been reduced by erosion to only moderate heights ; but it 
 is not improbable that their altitude originally was like th^t 
 of the loftiest ranges of the world, some of which haye been 
 formed and the others much uplifted during the last geologic 
 period. 
 
 The shortness of the time that has elapsed since the latest 
 glaciation of North America, according to the ' observations 
 and computations of N. H. Winchell, Andrews, Wright, and 
 Gilbert, shows that this cold epoch was not coincident with 
 the period of eccentricity of the earth's orbit, which is regarded 
 by Croll, Geikie, and Wallace as the primary cause of the Ice 
 age. Eccentricity, therefore, had no share in producing this 
 most recent glaciation, which was more intense and severe, 
 and probably more sudden and brief, than the earlier rery cold 
 epoch of the Ice age, as indicated by comparison of the mo- 
 rainic and other drift deposits. Furthermore, it seems proba- 
 ble that the Quaternary Glacial period, including its two or 
 more epochs of glaciation, each subdivided by episodes of tem- 
 porary retreat and readvance of the ice, besides the principal 
 interglacial epoch of warm or temperate climate, and perhaps 
 complete departure of the North American ice-sheet, was 
 wholly subsequent to the maximum eccentricity which the 
 
 * Prestwich's " Geology," vol. i, p. 300. 
 
 ■f " Geological Researches in China, Mongolia, and Japan," by Raphael Pum- 
 pelly, " Smithsonian Contributions," vol. xv, 1861, chap. vii. The conclusions 
 reached by Pampelly concerning this mountain system are fully confirmed by 
 the subsequent grand work of Baron Richthofen on the geology of Chifla. 
 
518 THE ICE AGE IN NORTH AMERICA. 
 
 earth's orbit attained two hundred thousand years ago. 
 Through all the past ages of geology, also, the earth has from 
 time to time passed through similar stages of increased eccen- 
 tricity, sometimes having a still higher maximum,* which we 
 should expect, in accordance with CroU's theory, to find re- 
 corded by deposits of glacial drift intercalated in the Tertiary, 
 Mesozoic, and Palaeozoic strata of circumpolar and temperate 
 regions. But the recentness of the Quaternary glaciatiou, and 
 the general absence of earlier drift formations,! excepting 
 within the Carboniferous and Permian periods, seem to demon- 
 strate that eccentricity has not been the primary cause of gia^ 
 ciation, either with the concurrence of climatic conditions and 
 changes of the course of winds and of oceanic currents such 
 as might attend its slight modifications of the seasons, while 
 the present arrangement and relative heights of land and sea 
 were unchanged, or, as Wallace suggests,J with much greater 
 elevation of the areas glaciated, which he thinks to have been 
 necessary, seconding the effects of eccentricity, for the accumu- 
 lation of ice-sheets. Indeed, we may well doubt that eccen- 
 tricity has exerted any determining influence in producing 
 unusual severity of cold either during the Quaternary or any 
 former period. 
 
 Elevation of broad areas, as half of N"orth America and half 
 of Europe, either synchronously or in alternation, to such 
 heights that their precipitation of moisture throughout the 
 year was nearly all snow, forming gradually ice-sheets of great 
 thickness, seems consistent with the conditions of the earth's 
 crust and interior, which are indicated by the changes in the 
 levels of glaciated countries. A molten magma beneath the 
 solid crust appears, in connection with contraction of the earth 
 
 * CroU's " Climate and Time," chap, xix, with plate iv, representing the 
 variations in the eccentricity of the earth's orbit for three millions of years before 
 A. D. 1800, and one million of years after it. 
 
 t Nordensldold reports that, in sections observed by him in Spitsbergen and 
 Greenland, including all formations from the Silurian to the Tertiary, and occu- 
 pying in the aggregate, as he estimates, not less extent than a thousand English 
 miles, he has never observed erratic blocks nor any evidence of glacial action. — 
 "Geological Magazine," II, vol. ii, 1875, pp. 525-532, and vol. iii, 1876, p. 266. 
 
 X " Island Life," chaps, viii, ix, and xxiv. 
 
THE CAUSE OF THE GLACIAL PERIOD. 519 
 
 and the formation of mountain-ranges, to afford an adequate 
 explanation of glaciation. It is probable that the great up- 
 lifts which are thus supposed to have caused ice-accumulation 
 were very slow in their progress, and that their effect upon 
 extensive continental areas was so distributed that the maxi- 
 mum changes in slope on theii borders would nowhere exceed 
 twenty or thirty feet per mile, while perhaps some portions 
 of the uplifted region would receive no change of slope. And 
 the subsidence beneath the weight of accumulated ice was 
 probably equally slow and similarly distributed, no limited 
 district being greatly changed. Excepting the rare instances 
 where disturbances of mountain-building or extraordinary ris- 
 ing or sinking of mountain-ranges were associated with these 
 movements, the contour of the country, with its valleys, hills, 
 and mountains, has remained in general the same from pre- 
 glacial time through the Ice age to the present with only 
 changes of slope, small in any limited tract, which in long 
 distances allowed great upheavals and depressions. The ele- 
 vation of the central part of glaciated areas, with downward 
 slopes on all sides, would favor the outward flow of the ice-sheets 
 and their erosion and transportation of the drift. But mount- 
 ains and hills jutted upward in ridges and peaks within the 
 moving ice-sheet, as they now stand forth in bold relief above 
 the lowlands ; and the ice with its inclosed drift was pushed 
 around and over them, some portions being deflected on either 
 side, and usually a larger part being carried upward across 
 their tops. Katahdin, the White Mountains, the Green Mount- 
 ains, and the Adirondacks, stood directly in the pathway of 
 the ice outflowing southeastward from the Laurentian high- 
 lands. Its thickness in northern New England and northern 
 New York seems to be measured approximately by the eleva- 
 tion of the highest of these summits above the adjoining low- 
 lands, about one mile ; but northward the ice-sheet evidently 
 was somewhat deeper upon the valley of the St. Lawrence, and 
 Professor Dana's estimate seems still reliable, that its maxi- 
 mum depth, lying on the water-shed between this valley and 
 Hudson Bay, was probably about two miles. 
 
520 THE ICE AGE IN NORTH AMERICA. 
 
 SUPPLEMENTARY NOTES. 
 By Warren Upham. 
 
 The twenty-one years which have elapsed since the prep- 
 aration of this chapter have not furnished any facts mate- 
 rially to modify the views here presented. The most impor- 
 tant additional discussions of the subject are those of Messrs. 
 Chamberlin and Sahsbury advocating an atmospheric the- 
 ory,* which they state as follows, when treating of the Permian 
 Glacial epoch. 
 
 "The increased area of the land, and its increased ele- 
 vation, give increased contact between the atmosphere and 
 ■the rocks of the earth susceptible of carbonation and oxida- 
 tion, as already indicated. As a result, the atmosphere 
 lost carbon dioxide and oxygen at a more rapid rate than in 
 the previous period." 
 
 Here, and in other extensive developments of this theory 
 by Chamberlin in the "Journal of Geology," it is definitely 
 shown that the supposed decrease of carbon dioxide, re- 
 garded as the chief cause of glaciation, is ascribed to in- 
 creased altitude of continental areas. In other words, the 
 new theory espoused by Chamberlin and Salisbury, depends 
 in the same way as my epeirogenic theory, called by them 
 the "hypsometric hypothesis," on exceptional continental 
 elevation. Each view recognizes two periods so preemi- 
 nently characterized by extensive ice-sheets, namely, the 
 Permian and the Pleistocene, that we must believe, from 
 the records of glaciation, that they each had much greater 
 land altitude, for large parts of the continents, than any 
 other period in all the vastly long ages of geologic time. 
 The great epeirogenic elevations preceding and causing both 
 the Permian and Pleistocene ice ages are well emphasized in 
 the foregoing pages; but there we had not learned how the 
 
 * See "Geology," vol. ii, pp. 655-677; vol. iii. pp. 424-446; also 
 above p. 
 
THE CAUSE OF THE GLACIAL PERIOD. 521 
 
 ordinary meteorologic conditions of high land elevation were 
 reinforced, in their tendency to produce ice-sheets, by the 
 concomitant depletion of atmospheric carbon dioxide. Now, 
 through the fruitful studies of Arrhenius, Chamberlin, and 
 others, we see how the great altitude of the Continents at 
 these two periods of great areas of long continued glaciation, 
 so very widely separated in time and therefore remarkably 
 unique and exceptional, worked in two ways, not only by 
 the common meteorologic effects, but also by the newly 
 recognized results of depletion of carbon dioxide, to give the 
 marvelous glacial periods thus ending Paleozoic and Ceno- 
 zoic time. 
 
 Further studies will give the proportional effectiveness 
 of these two ways by which great uplifts of the continental 
 areas have induced glaciation. The final theory will rest 
 not less on the sagacious early views of Dana, with their 
 further advocacy by Le Conte and other writers, including 
 Wright and myself, than on the very helpful work of Arrhen- 
 ius and Chamberlin in their added contribution to explain 
 how the land uplifts accumulated ice-sheets with snowfall 
 all the year upon their vast expanses. Indeed I yet think, 
 that the broad view of the causation of glacial periods as 
 given above was presented truly and vividly, with no more 
 than the proper emphasis onthe-very exceptional occurrences 
 of only these two periods of general continental glaciation. 
 
 Coming next to the great question whether the Pleistocene 
 ice-sheets of North America and Europe were wholly melted 
 away, as is argued by Professor James Geikie and less decid- 
 edly by Chamberlin and others, we cannot adduce sure 
 proofs for such conclusions from the central areas of these 
 great ice-sheets on the opposite sides of the Atlantic ocean. 
 The interior of New England and of British America, like 
 the central parts of Sweden and Norway, have not yet 
 revealed such sequence of glacial deposits and intervening 
 fossiliferous beds, of somewhat temperate faunas and floras, 
 
522 THE ICE AGE IN NORTH AMERICA. 
 
 as to give any conclusive evidences of complete departure of 
 the ice-sheets and their subsequent renewal to again spread 
 over nearly all of their former areas. Only in the peripheral 
 parts, broadly speaking, of these two immense ice-fields, are 
 proofs of successive stages of glaciation, divided by old land 
 surfaces and fossil-bearing stratified beds, either of the modi- 
 fied drift or of alluvial, lacustrine, or marine sedimentation. 
 
 Minnesota, somewhat far back from our southern lim- 
 its of the maximum glaciation, has well ascertained proofs 
 of so great recession of the borders of the North American 
 ice-sheet as to uncover the south half of this state, succeeded 
 by renewal of the snowfall and ice accumulation until the 
 borders of our continental ice-sheet again reached southward 
 as far as the lowan and the Wisconsin drift. The earlier 
 glaciation appears surely to have been of much longer dura- 
 tion than the later lowan and Wisconsin stages. Thus our 
 Pleistocene Ice age was much diversified and even very com- 
 plex, yet I would now far more confidently ascribe all our 
 North American drift formations to one prolonged and con- 
 tinuous glacial period, with great fluctuations of the glacial 
 border, especially in the interior of the continent, than to 
 regard our ice age as two-fold or three-fold, in the sense of 
 having its vast ice-sheet wholly melted away, or even nearly 
 so, with ensuing renewal of the snow and ice-fields. 
 
 Geologically very rare, an ice age would scarcely be dupli- 
 cated with so nearly the same limits of ice extension upon 
 half of our continent. The same general conclusion is also, 
 as I think, applicable to the European glaciation. Almost 
 inconceivable geologic duration divided the Permian and 
 Pleistocene Ice ages. In this most recent and geologically 
 short Ice age which has ended, as I surely believe, within the 
 last 10,000 to 5,000 years, at the threshold of the historic 
 period, I cannot think that the stupendous climatic changes 
 implied in the glaciation could permit complete repetition 
 of these continental ice-sheets in America and Europe, in 
 
THE CAUSE OF THE GLACIAL PERIOD. 523 
 
 each area so closely extending to nearly the same maximum 
 limits in the earlier and the later parts of this Glacial period. 
 It is better, until proofs are obtained in the central regions 
 of the drift areas on each continent, to regard their time of 
 glaciation as one and continuous, with much areal oscilla- 
 tion, such as is proverbial of weather, both during the gen- 
 eral stages of growth and departure. 
 
 My explorations of the Minnesota drift deposits, so far 
 as they appear to require great recession and later readvance 
 of the snow and ice accmnulation, may be cited in the final 
 reports of our state geological survey, the most notable of 
 these observations being as follows, supplementing Prof. N. 
 H. Winchell's observations of an interglacial forest bed in 
 Mower county and other localities of southern Minnesota.* 
 
 1. The exceedingly interesting and elsewhere unequaled 
 chains of lakes in Martin county, one of the central counties 
 of our most southern tier, I can explain only by regarding 
 them as proofs of a fully developed interglacial system of 
 drainage running there from north to south, which became 
 afterward ice-enveloped in the lowan and Wisconsin stages 
 of our Glacial period.t 
 
 2. Somewhat the same conclusion seems again enforced 
 by the section of the drift close southwest of New Ulm, in 
 Brown county, about 40 miles north of these chains of lakes.J 
 
 3. In the northern part of Chisago county, on the east 
 side of Minnesota, Rushseba township, in which Rush City 
 is situated, about 50 miles north of St. Paul and Minne- 
 apolis, has a considerable tract, § some 5 or 6 miles long and 
 of nearly as great width, where reddish-modified drift, spread 
 by streams flowing down from the receding northeastern 
 
 * See below p. 605. 
 
 t "Geology of Minnesota," vol. i, 1884, pp. 479-485, with the map 
 facing page 472. 
 
 X Ibid, vol. i, pp. 581-3, with section, and with map facing p. 562. 
 
 § "Geology of Minnesota," vol. ii, 1888, pp. 409-415, 417, 418, the 
 last giving the record of that well, with the map facing page 399. 
 
524 THE ICE AGE IN NORTH AMERICA. 
 
 lobe of the ice-sheet, forming for a time a land surface which 
 bore timber, was subsequently overspread by an ice-lobe 
 whose current was from the northwest to the southeast and 
 east. The overlying yellowish gray till, spread as a continu- 
 ous and nearly uniform bed only ten to twenty feet thick 
 and forming a nearly level expanse of so much extent, at 
 least 5 miles in diameter, has plentiful limestone fragments 
 from the northwest, being thus in remarkable contrast with 
 the red till deposits lying beneath the gray till in that region, 
 which came from the northeast and therefore has no lime- 
 stone. A well on this area encountering peat and decaying 
 fragments of wood in a water-deposited clay beneath the 
 gray till and at the top of the older underlying modified drift 
 gravel and sand, testifies that this was a land surface with 
 peat and forest trees, previous to the very latest glaciation 
 which brought the yellowish gray till.* 
 
 4. On the southern part of the area of the Glacial Lake 
 Agassiz, at Barnesville in Clay county, about 190 miles 
 northwest of the Twin Cities (St. Paul and Minneapolis), 
 a well penetrates twelve feet of till, and next beneath, in the 
 bottom of the well, went one foot into quicksand, " contain- 
 ing several branches and trunks of trees, thought to be tam- 
 arack, up to eight inches in diameter, lying across the well, 
 which, together with the inflow of water, prevented farther 
 digging." This well is on the till area of the village of Barnes- 
 ville, about eighty feet below the highest beach of Lake 
 Agassiz, which passes from south to north about three miles 
 east of this village. At the time of my survey of that region 
 and when this volume was published, in 1888, I considered 
 the occurrence of this interglacial bed within the area of the 
 glacial lake as good evidence that the ice-sheet in that inter- 
 glacial stage was melted back at least so far as to give out- 
 flow into Hudson Bay from the Red River Valley, draining off 
 the interglacial forerunner of Lake Agassiz. Subsequent 
 studies and general reasoning lead me, however, now to hold 
 * See above p. 184. 
 
THE CAUSE OF THE GLACIAL PERIOD. 525 
 
 the different view that probably the earlier interglacial lake 
 in this valley may have even cut its channel of southern out- 
 let, at the site of Brown's Valley, to a lower level than the 
 well in Barnesville, or that the attitude of the land then 
 was unlike what it now has, having then such an ascent from 
 south to north that the Barnesville locality in that inter- 
 glacial time was above the general surface of the region at 
 Brown's Valley, into which the River Warren, outflowing 
 from Lake Agassiz, cut its deep continuous valley. So I 
 now think that we have there, in the section of this well, 
 only evidence of an ice retreat (that is, a departure of the 
 outer part of the ice-sheet) so far north as to that region, 
 about halfway between the south and north boundaries of 
 this state.* My numerous papers show how, as I think, 
 good forests and other luxuriant vegetation may have 
 flourished near the border of the ice-sheet, accompanying 
 the recession of that border. 
 
 The questions are sure to be asked : Why is the boundary 
 of the glaciated region in the United States so irregular? 
 What was the cause of its withdrawing so far north in western 
 New York, and of its sudden bend to the south in eastern 
 Ohio, and of its lobe-like projections in southeastern Indiana 
 and southern Illinois ? And what was the cause, at a later 
 stage, of the lobate contour of the moraines . west of Lake 
 Michigan in Wisconsin, Iowa, Minnesota, and Dakota ? These 
 questions we can only answer by saying that the distance to 
 which the great American ice-sheet penetrated the southern 
 latitudes was evidently not dependent, to any great extent, 
 upon the elevation of the land over which it was compelled to 
 move. The ice did not uniformly move farther south where 
 there was a depression of the land, and the boundary does 
 not ordinarily retreat to the nortii on account of the higher 
 elevations opposing its progress. South of New England the 
 
 * Geology of Minnesota, vol. ii, pp. 661-2, and 668; with the map 
 facing p. 656. 
 
526 THE IGE AGE IN NORTH AMERICA. 
 
 glacial front was at the sea-level, and tlie ocean itself may 
 have kept it from advancing farther. In Pennsylvania the 
 boundary-line crosses the Alleghany Mountains diagonally, 
 being nearly as high on Pocono Mountain, in the eastern part 
 of the State (about two thousand feet), as in the southwestern 
 part of 'Sew York, where it is sixty or seventy miles farther 
 north. In Ohio the highest portion of the State is in Logan 
 county, almost directly north of Ripley, in Brown county, 
 the most southern point reached in that State. The unglaci- 
 ated, portion in southern Indiana, projecting about seventy 
 miles northward into the glaciated region, is indeed some- 
 what higher than the land on either side, but nowhere is its 
 elevation greater than that of the larger portion of Ohio. 
 The farthest extension of the ice in Illinois is closely coinci- 
 dent with the trough of the Mississippi Valley, and westward 
 of the Mississippi River the edge of the ice withdrew farther 
 and farther north pretty nearly in proportion to the increas- 
 ing elevation of the country, until, at Sim's Station, in the 
 vicinity of Bismarck, Dakota, it is nineteen hundred and sixty 
 feet above tide, and continues thence to ascend northward to 
 a height of three or four thousand feet in the upper valley of 
 the Saskatchewan. 
 
 There is, thus, a general conformity in its southern exten- 
 sion to the valley of the Mississippi. The ice of the Glacial 
 period as a whole did, indeed, move down that great valley, 
 and its most southern point is in the middle of it, where it 
 it is not more than five hundred feet above the sea ; but it is 
 evident that the total width of the southern portion of this 
 ice-sheet is so great, and the slope itself so slight, that this 
 depression could not have been the main cause of the great 
 extension to the south in Illinois. The width of the glaci- 
 ated area from southern Ohio to eastern Kansas, on the thirty- 
 ninth parallel, not far from the extreme limit of glaciation, 
 is nearly a thousand miles. The cause, therefore, of the lo- 
 bate character of the southern boundary must, in all proba- 
 bility, be sought in the irregular areas of excessive snow-fall 
 existing to the north during the advance and continuance of 
 
THE GAUSE OF THE GLACIAL PERIOD. 527 
 
 the Glacial period. From a glance at the map it would seem, 
 therefore, that the greatest area of snow-fall was somewhere 
 in the vicinity of Lake Superior, and that a secondary area of 
 large snow-fall was in the vicinity of Labrador ; for the south- 
 em boundary of the glaciated region consists essentially of the 
 arcs of two circles whose centers would fall within the areas 
 indicated. 
 
 In speaking of these two areas as centers of radiation for 
 the glaciers of the great Ice age in North America, it is not 
 aflSrmed that the movement received no impulse from still 
 farther north. It is not improbable that the upper portion 
 of Baffin Bay was filled and crossed by the glaciers still 
 lingering over the continental area of Greenland, and that 
 this Greenland ice aided in the movement which covered the 
 northern part of the United States with its icy mantle. But 
 it was probably by reaction rather than by direct action that 
 aid came from that quarter. The accumulations to the north 
 prevented an outflow in that direction, and so compelled a 
 southerly movement from the vicinity of the Laurentian 
 highlands. It is not, however, probable that any Greenland 
 ice ever reached the United States. None of the bowlders 
 so common in the United States are, so far as known, more 
 than a few hundred miles distant from their parent ledges. 
 There was doubtless all the while an ice-stream down Baf- 
 fin Bay toward the Atlantic Ocean, with a movement into 
 it from both sides. But even if this were not the case, the 
 areas south of Hudson Bay and in Labrador would still be 
 the predominant influence in determining the southern out- 
 line of the glacial boundary. The snow that piled up from 
 year to year over those centers would be compelled to move 
 off in the lines of least resistance. Now, ice can be an ob- 
 struction to other ice as well as to water ; and what the 
 Greenland glacier probably did was to close up the upper 
 portion of Baffin Bay, so that the excess of snow-fall over 
 the subcenter referred to as north of Lake .Superior could 
 not move off to the northeast, but was compelled to spend 
 all its force in a southerly movement. It is evident also that 
 
528 THE ICE AGE IN NORTH AMERICA. 
 
 every subcenter where the snow-fall was larger than the 
 average would, to some extent, make its influence felt upon 
 the shape of the margin. 
 
 Here is a field for the mathematician. "When thfe prop- 
 erties of ice are more fully understood from experimental 
 investigations, and the laws of its fluidity brought under 
 mathematical formulae, it will doubtless be possible, from a 
 study of the contour of the glacial boundary, to calculate the 
 position of all the principal areas of largest precipitation 
 during the Glacial period. 
 
 Those remarkable lobe-like projections in southern Ohio 
 and Indiana, for example, indicate subcenters of accumu- 
 lated ice not far back from the margin. The still' more 
 remarkable prolongation of the loops in the kettle-moraine 
 in Wisconsin, and its extension through the States farther 
 west, point, as President Chamberlin sagaciously and cor- 
 rectly supposes, not merely to greater snow-fall over the 
 regions from which the ice-movement radiated, but to the 
 conservative influence of the deeper valleys and depressions 
 to the north, which were filled with ice. These loops of the 
 kettle-moraine sustain a remarkable relation to the valley of 
 Green Bay, and to the northeast and southwest axis of Lake 
 Superior, while the ice-lobe which occupied the valley of the 
 Minnesota and extended to the center of Iowa is evidently 
 related to the great valley of the Red River of the North. It 
 is not improbable that the depth of ice in such a depression 
 as Lake Superior would, by its very thickness, tend for a long 
 time to increase the snow-fall over its own area, and in other 
 ways to resist the antagonistic agencies which were gradu- 
 ally driving the ice-front back to the north. The driftless 
 area of southwestern Wisconsin is situated just where it es- 
 capes these several ice-movements dominated by the depths 
 of Lake Michigan and Lake Superior, and it is to this day— 
 as Professor Dana has pointed out^ — a region of light precipi- 
 tation. ' 
 
 If this discussion of the cause of the Glacial period 
 seems unsatisfactory, the justification is that the presient' 
 
THE CAUSE OF THE &LACIAL PERIOD. 529 
 
 knowledge of the whole subject is in an extremely unsatis- 
 Sactory condition ; and in this, as in other things, the first 
 requisite of progress is to squarely face the extent of our 
 ignorance upon the question. The causes with which the 
 glacialist deals are extremely complicated, and yet they are 
 of such a nature as to invite investigation, and to hold out 
 the hope of increasing success in mastering the problem. 
 There is opportunity yet for some Newton or Darwin to 
 come into the field and discover a clew with which success- 
 fully to solve the complicated problem which has so far baf- 
 fled us. To the genuine investigator it is a source of inspi- 
 ration rather than of depression to have such an untrodden 
 field before him. 
 
 Conclusion. — Geology is pre-eminently a terrestrial sci- 
 ence, and there is danger of a misdirection of effort when 
 the geologist forms an alliance with the astronomer. Astro- 
 nomical data are so largely theoretical, and the quantities 
 which the astronomer multiplies are often so nearly infinitesi- 
 mal, that quantitative error is in peculiar danger of becom- 
 ing enormous in large calculations. Hence, we can not count 
 it altogether an advantage that astronomical speculation has 
 been so rife during the past few years in determining the 
 causes and the chronology of the G-lacial period. 
 
 Of the various cosmical theories to account for the Gla- 
 cial period, that of Mr. CroU is by far the most plausible and 
 interesting. It must be admitted that his data concerning 
 the various distances at which the earth is found from the 
 sun during the winters of different periods, and concerning 
 the periodical variations in the length of the winters, rest 
 upon well-ascertained facts. It is no doubt true that about 
 one hundred thousand years ago the winters were at times 
 several days longer than now, and the northern hemisphere 
 was receiving daily considerably less heat than now, since it 
 was several millions of miles farther away from the sun. 
 
 But the distribution of the earth's heat by winds and 
 oceanic currents is a subject concerning which much less is 
 Icnown. The phenomena presented in a hot-house are puz- 
 
530 THE ICE AGE IN NORTH AME-RIOA. 
 
 zling. The heat of the sun goes through the glass, but can 
 not readily get out again. It is well known, also, that a 
 slight increase of moisture in the atmosphere, or a slight 
 film of cloud over the sky, prevents a frost. The real prob- 
 lem lies, therefore, in the meteorological field. Now, during 
 Mr. CroU's " aphelion " winters, the summers are in " perihel- 
 ion," and the summer heat in this hemisphere while in peri- 
 helion is more intense than at other times. In fact, the 
 earth receives at all times the same absolute amount of heat 
 from year to year. Thus, we can not avoid the conclusion 
 that the predominant influence in climate may consist in the 
 power of moisture-laden atmosphere to retain and transport 
 the heat, thus determining its distribution. As a matter of 
 fact, we find that the equator is not so hot as theoretically it 
 should be, and the arctic regions are by no means so cold as, 
 on CroU's theory, they ought to be. The difference between 
 the mean temperature on the equator and that at the coldest 
 point on the sixty-seventh parallel is really only about 75" 
 Fahr. ; whereas, if the temperature at these points were pro- 
 portionate to the amount of heat received from the sun, the 
 difference would be 172°. Such facts as these lead meteor- 
 ologists to regard Mr. CroU's theory with much less favor 
 than formerly. 
 
 But the glacialist is not so much concerned to know the 
 ultimate cause of the Glacial period as he is to collect the 
 facts which characterize the period. The truth is, that the 
 meteorological forces of Nature are so powerful and complex 
 that there is an embarrassment of riches in the field of glar 
 cial theory. It is easy to see that a slight increase of snow- 
 fall over the Alps would cause a permanent enlargement of 
 all the glaciers of Switzerland, and threaten every interest of 
 that republic, and perhaps of central Europe ; for the ulti- 
 mate effects of a climatic disturbance in one such center can 
 not well be estimated. 
 
 Much light upon the condition of things during the Gla- 
 cial period in America must yet come from a careful study 
 of the lobate contour of the terminal moraines. The shapes 
 
THE CAUSE OF THE OLAOIAL PERIOD. 531 
 
 of these moraines, coupled with what may yet be learned 
 concerning the nature of ice and concerning the shifting 
 course of the atmospheric currents, will, in all probability, 
 eventually furnish the data for the solution of the question 
 of the true cause of the Glacial period. A fair field here 
 invites the active and prolonged attention of some future 
 meteorological Darwin or Newton, and promises immortality 
 such as they have attained. 
 
CHAPTER XX, 
 
 THE DATE OF THE GLACIAL PEEIOD. 
 
 Two causes have combined in recent years to favor erro- 
 neous calculations concerning glacial chronology. Of these, 
 the first has been the almost unquestioned acceptance of the 
 astronomical theory subjected to examination in the preced- 
 ing chapter. If Mr. Croll's theory of the cause of the Gla- 
 cial epoch is correct, then we should no longer speak of an 
 ice age, but of a succession of such ages, whose dates could be 
 readily determined from a table showing the periods of high- 
 est eccentricity in the earth's orbit. According to this table, 
 the modem period most favorable to the production of a 
 glacial epoch began about two hundred and forty thousand 
 years ago and ended about seventy thousand years ago. The 
 whole intervening time was one of high eccentricity, when, 
 during the recurring intervals in which the winters occurred 
 at aphelion, the excess of winter over summer ranged from 
 fourteen to twenty-six days, and the intensity of the heat 
 received from the sun during those aphelion winters was ten 
 per cent less than at the present time. During the time in- 
 tervening between seventy thousand and two hundred and 
 forty thousand years ago, there occurred, therefore, according 
 to this theory, a succession of glacial and interglacial periods 
 in which geologists and archaeologists are invited to distrib- 
 ute their remarkable discoveries concerning glacial man. 
 Undue confidence in this theory has had no small influence 
 in diverting attention from the more legitimate lines of in- 
 vestigation. 
 
 A second source of error has been an incorrect interpre- 
 
THE DATE OF THE GLACIAL PERIOD. 533 
 
 tation of Lyell's principle of uniformity in Nature's opera- 
 tions. This has led to an exaggerated estimate of everything 
 pertaining to geological time. There is a prevalent popular 
 impression that all geological events happened a great while 
 ago. This impression arises largely from the imperfect ap- 
 prehension of the extent to which changes are now going on 
 in the world. In reality, however, Lyell's greatest service 
 consisted in quickening our conception of the instability of 
 the present condition of things, and of the intensity of 
 present natural forces. He riveted the attention of his 
 readers upon the cumulative effect of such earthquakes as are 
 now of daily occurrence, and occasionally of enormous influ- 
 ence, and continually reminded them of the frequency and 
 intensity with which new volcanoes are now from time to 
 time bursting forth. Contimuil/y, therefore, rather than uni- 
 formity, is the word which most properly expresses the prin- 
 ciple underlying the theories of this great geblogist. A pe- 
 rusal of his works makes it evident that evolution, and not 
 dull repetition, characterizes the processes of Nature. There 
 is therefore really nothing in Lyell's working principle to 
 raise any antecedent presumption in favor of an extreme 
 antiquity for the Glacial period. 
 
 On the contrary, the present tendency, both among as- 
 tronomers and geologists, is to diminish estimates of geologi- 
 cal time in almost every period. The hundreds of millions 
 of years claimed, not long ago, as necessary for the deposition 
 and metamorphism of the geological strata, and for the ele- 
 vating and eroding forces to produce the present contour of 
 the earth's surface, have on geological evidence been reduced 
 to much more moderate limits. Thirty million years is now 
 shown to be ample for the deposition, by forces still in op- 
 eration, of all the sedimentary strata of which we have 
 knowledge. At the same time the astronomers affirm that 
 life can not have existed on the earth earlier than twelve 
 million or fifteen million years ago.* Before that period 
 
 * See Newcomb's "Popular Astronomy," pp. 6i:S-61». 
 
534 THE ICE AGE IN NORTH AMERICA. 
 
 the radiation of the sun's heat was so intense that life must 
 have been impossible upon our globe. 
 
 But he who pauses to reflect upon how long a period one 
 million years is, and takes the pains to multiply the annual 
 changes of the present time by that number, will not feel 
 cramped by the limits which astronomers are now setting to 
 geological time. In this general shortening of our concep- 
 tion of geological periods,' the evolutionists also find no small 
 relief in the more moderate estimates made concerning the 
 date of the close of the Glacial period ; for it is very clear 
 that the changes in species since the great Ice age are trifling. 
 The flora and fauna of the world during the Glacial period 
 were essentially the same as those of the present time. Even 
 man is believed to have been an inhabitant of America, as 
 well as of Europe, before the ice had withdrawn from the 
 head-waters of the Delaware Eiver, and from the mountains 
 of Scotland and the north of England. If these changes in 
 the organic world have been so slight since the Glacial epoch, 
 it follows that, the further back that period is placed in time, 
 the greater are the difficulties of the evolutionists. The 
 more the evolutionists are limited in time by the astrono- 
 mers, the more do they need a rapid rate of change as the 
 basis of their calculations. If, therefore, the Glacial period 
 should prove to have ended only ten thousand years ago in- 
 stead of seventy thousand, the Darwinian would be relieved 
 from no small embarrassment. Tlius, so far as there is likely 
 to be any odium theologicum in the case, the desire to sup- 
 port a short biblical chronology and the counter-desire to dis- 
 credit Darwinism, and vice versa, may be left to counteract 
 each otlier. 
 
 In view of the doubt expressed in the preceding chapter 
 concerning Mr. Croll's theory, it does not seem proper for 
 geologists to rest satisfied with mere astronomical calcula- 
 tions respecting glacial chronology. We may, therefore, be 
 permitted to turn to the more congenial task of considering 
 the direct geological evidence bearing on the question. In 
 this field there are three classes of facts to which we can 
 
536 THE ICE AGE IN NORTH AMERICA. 
 
 confidently look for liglit : 1. The amount of erosion and 
 disintegration which has occurred since the Glacial period. 
 2. The extent to which lakes and kettle-holes have been fiUed 
 with sediment. 3. The apparent freshness of organic re- 
 mains in glacial deposits. 
 
 Beginning with the extent of erosion which has taken 
 place since the withdrawal of the ice, our attention is, natu- 
 rally enough, directed first to the gorge below the Fails of 
 Niagara. How this comes to be a glacial chronometer has 
 already been seen.* The old outlet of Lake Erie, which 
 must have existed as the result of preglacial erosion, was 
 filled up during the great Ice age, and the Niagara Kiver is 
 the outlet of the pond thus created. Originally the water 
 plunged over the escarpment at Queenston, about seven 
 miles below the present cataract. This escarpment is formed 
 by an outcrop of a thick deposit of Niagara limestone, the 
 summit of which is about three hundred feet above the level 
 of Lake Ontario. This is underlaid by a softer rock, which 
 is more rapidly disintegrated than the upper strata ; hence 
 the upper strata always project beyond the lower, and every- 
 thing favors the continuance of the cataract at the head 
 of the gorge as it wears back. The problem is to de- 
 termine how long the Niagara River has been in wearing 
 out the gorge between Queenston and the present cata- 
 ract. The solution of that problem will furnish an answer 
 to the other question, How long has it been since the ice- 
 barrier across the valley of the Mohawk was removed, so 
 that the dammed-up waters of Lake Ontario and Lake 
 Erie would subside sufficiently to permit the formation of 
 the cataract at Queenston and the commencement of erosion 
 in the present gorge ? The problem is comparatively simple, 
 and its bearing upon the date of the Glacial period is clear. 
 
 The Falls of Niagara have receded about seven miles. 
 The conditions have been from the first so nearly uniform 
 that the present rate of erosion can not differ largely from 
 
 * See chapter xii, p. 303 et seq. 
 
THE DATE OF THE GLACIAL PERIOD. 537 
 
 the average rate. Tliere is some evidence that a part of the 
 work above the Whirlpool had been done by a local stream 
 
 Pig. 133.— Section of strata along the Niagara gorge from the falls to the lake. 1, 3, strata 
 of hard rock ; 8, i, of soft rock. 
 
 which formerly passed from the "Whirlpool westward to St. 
 Davids, since there is no doubt of the existence of a filled-up 
 preglacial channel running from the Whirlpool to St. Dav- 
 ids. But the evidence that this channel extended above the 
 Whirlpool toward the present cataract is so imperfect that we 
 must leave it out of the question, and take the whole length 
 of the gorge from Qiieenston to Niagara as our dividend. 
 The problem remaining is to find the rate of recession, and 
 this will serve as a divisor. 
 
 The comparative youth of the Niagara gorge is evident 
 from the present condition of its mouth at Queenston. This 
 is narrow, and its walls abrupt ; but it is well known that,' by 
 the inevitable action of natural forces, the mouth of a river- 
 gorge must become, in process of time, very much enlarged, 
 since from the beginning its sides have been exposed to 
 the eroding action of the elements and to the undermin- 
 ing action of the river. In the unglaciated region the 
 mouths of such gorges are universally wide and V-shaped, 
 and the banks much obscured at the bottom by the accumu- 
 lation of debris. In this respect the mouth of the present 
 gorge at Queenston is in striking contrast with that of the 
 old gorge which opened at St. Davids. As will be seen by 
 reference to the map, this, though narrower where it left 
 the Whirlpool than the present main gorge below the Whirl- 
 
Pig, 134.— Map of the Niagara River below the falls, ehowin^ the bnried channel from 
 the whirlpool to St. Davids. Small streams a, b, c, fall into the main gorge over a 
 rocky escarpment. No rock appears in the channel at d, but the rocky escarpment 
 reappears at c. 
 
THE DATE OF THE GLACIAL PERIOD. 539 
 
 pool and not over half as long, is still at its mouth by St. 
 Davids several times as wide as that of the present Niagara 
 gorge at Queenston. 
 
 Coming to the main question, and taking the whole of 
 the gorge from Queenston to the present cataract as the 
 work done by the Niagara Kiver since the ice-barrier in the 
 valley of the Mohawk gave way, the problem is to find the 
 rate of recession. Until very recently the estim.ates of this 
 rate have been scarcely more than mere guesses. The emi- 
 nent French glacialist Desor thought it could not have been 
 greater than one foot in a century, which would place the 
 beginning back 3,500,000 years. In 1841 Sir Charles Lyell 
 and Professor James Hall examined the gorge together ; and 
 Sir Charles, in his lectures in Boston before tiie Lowell Insti- 
 tute soon after, estimated that the maximum rate of reces- 
 sion could not be greater than one foot a year, which would 
 fix the minimum date of its beginning at about thirty-five 
 thousand years ago. On the contrary, all the guides of that 
 period who had observed the falls for many years, were con- 
 fident that the rate of recession was as much as two feet a 
 year ; * while Mr. Bakewell, an eminent English geologist, who 
 had given much personal study to the question, estimated 
 that, for the forty years previous to 1830, the rate of recession 
 had been about three feet a year. Mr. Bakewell's son care- 
 fully reviewed the phenomena again in 1846, in 1851, and in 
 1856, and found no occasion to revise his father's estimate.f 
 
 To furnish the basis for more accurate calculations. Pro- 
 fessor James Hall had a map of the falls made in 1842, from 
 a trigonometrical survey, so that there should be a fixed 
 standard for future comparison. Within the past few years, 
 accurate surveys have again been made, both by the geolo- 
 gists of the State of New York, and by members of the 
 United States Coast Survey. In 1886 the American Associa- 
 tion for the Advancement of Science held its annual meeting 
 
 * Lyell's " Travels in America '' (first series), vol. i, p. 27. 
 
 f "American Journal of Science," vol. Ixxiii, 1857, pp. 87, 93. 
 
540 THE ICE AGE IN NORTH AMERICA. 
 
 at Buffalo and great interest was naturally centered upon this 
 question of the rate of the recession of the falls. Mr. G. K. 
 Gilbert, of the United States Geological Survey, whose au- 
 thority is unsurpassed on such subjects, gave it as his conclu- 
 sion that the "maximum length of time since the birth of the 
 falls, by the separation of the lakes, is only seven thousand 
 years, and that even this small measure may need significant 
 reduction." At the same time Mr. R. S. Woodward,* of 
 Washington, made a new survey, and gives the results defi- 
 nitely as follows: The length of the front of the Horseshoe Fall 
 is twenty-three hundred feet. Between 1842 and 1875 four, 
 and a quarter acres of rock were worn away by the recession 
 of the falls. Between 1875 and 1886 a little over one acre 
 and a third disappeared in a similar manner, making in all, 
 from 1842 to 1886, about five and a half acres removed. 
 
 Subsequent surveys have amply supported these conclu- 
 sions. From the survey made in 1905, by Mr. Carvel Hall, 
 state engineer of New York, it appears that the recession of 
 thfe Horseshoe Fall (which is where the principal volume 
 of water descends) during the sixty-three years between 
 1842 and 1905 was 333 feet, or at the rate of 5.3 feet per 
 annum 
 
 The foregoing estimates concerning the recession of the 
 Niagara gorge assume a uniform rate, and that all the work 
 has been done since the glacial period. As to the first of 
 these assumptions, Dr. Julius Pohlman,t of Buffalo, adduces 
 some evidence to show that the present course of the Niagara 
 from the Whirlpool to Queenston follows an old line of drain- 
 age, in which a small stream had eroded a shallow valley 
 previous to the ice period, and thus, by reducing the thick- 
 ness of the upper layer of hard limestone along its course, 
 had greatly facilitated the work of recession, when the whole 
 torrent of Niagara began to pour over the escarpment. Dr. 
 Pohlman has also greatly increased our conception of the 
 work already done before the Glacial period by the stream 
 which had its exit from the Whirlpool to St. Davids. This 
 
 • Report in "Science," September 3, 1886. 
 
 t "Transactions of the Amer. Institute of Mining Engineers," 1888. 
 
542 THE ICE AGE IN NORTH AMERICA. 
 
 stream, composed of the waters of the Tonawanda and Chip- 
 pewa Creeks, was of considerable extent, and by its action 
 had doubtless predetermined the course of the present river 
 above the Whirlpool, and may actually have worn a consid- 
 erable part of the present gorge above the Whirlpool. 
 
 Another element of uncertainty, which has led Mr. Gil- 
 bert and others to retract their former views, or at least to 
 hold them in suspense, relates to the variations of the water 
 supply since the beginning of the erosion. 
 
 It should, however, be noted that the erosion at Niagara 
 began long before the close of the Glacial period, namely 
 when the ice had melted off from the Mohawk Valley so as 
 to permit the drainage to take that course to the Hudson, and 
 lower the level of the existing glacial lake to that of the col 
 at Rome, N. Y. This would permit erosion to begin at the 
 mouth of the Niagara gorge, long before the ice had retreated 
 from the lower St. Lawrence Valley and from Canada in 
 general. 
 
 A most interesting state of things respecting the varia- 
 tions of the water supply at Niagara comes to light in coimec- 
 tion with the differential northerly depression of land during 
 the Glacial period, and its re-elevation after the disappearance 
 of the ice. From the fact that there was a northerly depres- 
 sion of 600 feet at Montreal, and presumably as much in the 
 northern basin of the Great Lakes, it follows that upon the 
 melting off of the ice from the Ottawa Valley, and from the 
 water parting between it and Lake Huron, the drainage might 
 for the most part be diverted in that direction, leaving the 
 Niagara with only that supply of water which would be fur- 
 nished by the local basin about the east end of Lake Erie. In 
 1892, 1 was sofortunate as to find clear evidence of this outlet 
 leading across from liake Nippissing, past the town of North 
 Bay, into the Mattawa River and thence into Ottawa at the 
 to^vn of Mattawan. The col at North Bay is less than 100 
 feet above the present level of Lake Huron, while the evi- 
 
THE DATE OF THE GLACIAL PERIOD. 5-13 
 
 dences of a post-glacial flow of water in enormous quantity are 
 perfectly clear. At Mattawan there is an enormous delta 
 of bowlders where the valley of the Mattawa joins that of the 
 Ottawa. Many of the bowlders are several feet in diameter, 
 and they are all waterworn. Moreover, the bowldery delta 
 has been pushed out into the Ottawa Valley so as to dam the 
 river and create a deep lake-like expansion above and a long 
 series of rapids below. In confirmation of the theory that 
 there was a flow of water through this channel for a consider- 
 able time Mr. Taylor found miniature pot-holes worn in 
 some of the large bowlders of the delta terrace at Mattawan. 
 
 Of course while the drainage of the Upper Great Lakes 
 was diverted around to the St. Lawrence by way of the Ottawa 
 Valley, the recession of the Niagara gorge was practically at 
 a standstill. It is important therefore to ascertain how long 
 a time this continued. Calculations upon this point will 
 largely depend upon the question of how rapidly the post- 
 glacial re-elevation of the region went on. Happily we have 
 much evidence upon this point, all of which indicates a rapid 
 rate as compared with that which is now going on. 
 
 The most important evidence comes from Dr. Upham's 
 study of the shore lines of the glacial Lake Agassiz which 
 spread over the valley of the Red River of the North (see 
 page 401). This temporary lake covered more than 100,000 
 square miles and its shore lines are easily traced for hundreds 
 of miles, like railroad embankments, across the prairie coun- 
 try of that region. There are several series of these shore 
 lines, at successively higher levels. But at the head of the 
 valley where the outlet was through Big Stone and Traverse 
 lakes into the valley of the Minnesota River, the beaches are 
 approximately at the same level. On proceeding northward, 
 however, while the lower beach remains nearly horizontal, the 
 upper one rises until in latitude 51° 52,' 200 miles north of 
 the international boundary, it is 400 feet above the lower 
 shore line. Thus it appears that during the existence of this 
 
Fig, 136 — Exposure of Niagara shale in Niagara gorge. TPliotoby Dutton). 
 
 191 57" 140 
 
 142 
 
 I .1 .1 . I. 
 
 ViV.' i 'i 
 
 I I I 1, 1- 
 
 ) NIAGARA '.".J.... 
 
 CLINTON ! 
 
 MEDINA ;" 
 
 770 
 
 Fig. 137— Diagram showing small amount of actual enlargement of the mouth of Niagara 
 Gorge at Lewlston. 
 
THE DATE OF THE GLACIAL PERIOD. 545 
 
 lake there was a rise of 400 feet in the northern part while 
 there was a rise of but a few feet at the southern end. 
 
 These facts give us a chance to estimate the rate of this 
 differential rise in the land lying north of the glacial border 
 which has been going on up to the present time, and thus 
 furnishes data from which to calculate the length of time dur- 
 ing which the depression at North Bay was sufficient to divert 
 the water of the Upper Great Lakes from Niagara. From the 
 data collected by Dr. Upham during his investigations of 
 Lake Agassiz he concludes that its entire existence could not 
 have been more than 2,000 years and probably was not more 
 than 1,000 years. 
 
 The facts upon which Dr. Upham relies, are: 1. The small 
 size of the deltas deposited on the margin of the lake by the 
 great rivers entering from the west; 2. The small size of the 
 ridges themselves; 3. The limited extent of the dunes about 
 the southern end of the lake. 
 
 1. The most important rivers which formed deltas in the 
 lake are the Cheyenne, the Assinniboine and the Saskatchewan, 
 which all come in from the region to the westward which was 
 free from ice during the greater part of the time of the exist- 
 ence of the lake. The gradient of these streams is rapid, and 
 the supply of sand and gravel within their reach is abundant. 
 Yet their delta deposits at the level of the beaches is small, 
 and entirely inconsistent with the continuance of the lake for 
 more than 1,000 or at most 2,000 years. 
 
 2. The shore lines, or beaches, are very much smaller than 
 those around Lake Erie, which, as we elsewhere show, could 
 not have been more than 2,000 to 3,000 years in forming. 
 
 3. The dunes at the south end are not over one-tenth the 
 size of those at the south end of Lake Michigan, which demon- 
 strably were not over 10,000 to 15,000 years in forming. 
 
 In explanation of this point it is necessary to call attention 
 to the facts concerning the dunes south of Lake Michigan. 
 These are very prominent features along all the railroads 
 
in 
 
 ^ 
 
 i^ 
 
 ^,-^ 
 
 ^^ 
 
 
 HH^ 
 
 
 
 
 s 
 
 i'-.i'j*.-, 
 
 
 
 mm 
 
 '.I "■ T"' 
 
 ..^i!5\;, "^-^ 
 
 "^^'-sBi-. ■ ~ •*. 
 
 ■ I 
 
 
 -^^^ 
 
 fH 
 
 ^^^^M 
 
 •^ •=.■■■ 
 
 '■: \ 
 
 
 p!p|i 
 
 E 
 
 ^^■1 
 
 
 Fig, 138 — Photograph looking north-wost towards St. Davif'a showing the excessive en- 
 largement of themonthof thepreglaclal clianncl. 
 
 Fig. 139 — Section, drawn to equal vertlcaland horizontal scale. showing enlargement of 
 Niagara gorge on the ea.st side at Its mouth at Lcwlston: 1, Niagara limestone. 
 20 to 30 feet : 2, Niagara shale. 70 feet ; 3. Clinton limestone. 20 to 30 feet ; 4. Clinton 
 and Medina shale. VOfeet; S.Quartzoae Medina sandstone. 20 to 30 feet; 6. softer 
 Medina sandstone. 120 feet above water level. 
 
THE DATE OF THE GLACIAL PERIOD. 547 
 
 entering Chicago from the east, but they are limited in extent, 
 and are in process of formation at the present time, the rate 
 of which can be approximately calculated. Lake Michigan 
 is now a closed body of water at the south end, and it is eating 
 into its western banks and bluffs at a rapid rate, the shelf 
 eroded by the waves since the departure of ice from its central 
 depths being about seven miles wide. The shingle, gravel 
 and sand derived from this erosion of the banks is carried along 
 the west shore southward past Chicago to the south end of 
 
 Pig. 140 — Hypothetic hydrography of the Great Lakes at a date after the melting of the 
 great glacier from the St. Lawrence Valley . 
 
 the lake, where it is taken up bytlie wind and blown outward 
 to form the dunes which are no'iv so prominent a feature in 
 the landscape. It has been important for various reasons to 
 learn how fast the sand is being carried past the Chicago 
 front, so that engineers have made very careful estimates. On 
 comparing the rate at which the material is being carried , 
 past Chicago, with the total amount of sand contained in the 
 dunes at the south end of the lake, it appears that the process 
 cannot have been going on more than 10,000 years. 
 
 Now, since Dr. Upham estimates that the dunes at the 
 south end of glacial Lake Agassiz are not over one-tenth the 
 
648 THE ICE AGE IN NORTH AMERICA. 
 
 size of those south of Lake Michigan, those on Lake Agassiz 
 would have been formed in about 1,000 years. Hence this 
 differential northerly elevation of land over the basin of 
 Lake Agassiz to the extent of 400 feet must have taken place 
 within that limited period. Such being the ascertained rate 
 of elevation in the Red River Valley, it is altogether probable 
 that the rise in the land at North Bay would not occupy a 
 much longer period, for the conditions Tvith respect to the 
 glacial ice and its recession are nearly alike in both regions. 
 In addition to this evidence adduced by Dr. Upham, I had 
 long before called attention to the small amount of erosion 
 which had taken place in the delta at Mattawan since the 
 glacial outlet there had been closed. 
 
 Another independent line of evidence indicating the 
 brevity of the past life of the Niagara gorge is drawn from a 
 study of its width at the mouth. In 1898 and 1899 I was 
 deputed by the New York Central Railroad to study the lower 
 part of the eastern side of the gorge, to shed what light I 
 could upon the stability of the conditions surrounding the 
 road bed built along the face of the gorge. Every facility for 
 examination and measurement was granted me. Briefly, the 
 results were as follows: the width of the river at the mouth of 
 the gorge is 770 feet, which is practically the original width of 
 the gorge, for the d^hris falling down has prevented the stream 
 from enlarging its channel at the base of the cliff. 
 
 Assuming that the cliff was originally perpendicular, 
 measurements showed that the strata at the summit had 
 receded on the east side only to the extent of 388 feet, making 
 the total width of the top of the gorge at the mouth 1,553 
 feet, on the supposition that the west side had been worn 
 away as fast as the east side had been. But various irregulari- 
 tiespreventedasaccuratemeasurementsonthatside. Nowthis 
 subaerial erosion of 388 feet from the top of the gorge on one 
 side indicates the removal of an inverted section of the face 
 of the gorge, with a base of 388 feet and a height of 340 feet, 
 
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THE DATE OF THE GLACIAL PERIOD. 549 
 
 the height of the chff at this point. If the subaerial erosion 
 of the face of the gorge proceeded at the rate of one-quarter 
 of an inch per annum, the material would have been removed 
 in less than 10,000 years. That this rate is not excessive 
 was shown both from the vast amount of debris that is now 
 annually precipitated upon the railroad track, and. from actual 
 measurements of the extent to which the hard strata of lime- 
 stone had been undermined since the track was laid, in 1854, 
 when it was found that the underlying Clinton and Niagara 
 shales had worn away more than three inches a year, leaving 
 the harder strata to project from thirteen to fourteen feet. 
 As illustrating the rapidity of erosion from the sides of the 
 gorge it is in point to remark that in 1898 there fell off at one 
 time from the face of the cliff on the east side of the Whirlpool, 
 100,000 tons of rock, whereas the amount which we have 
 supposed to fall away aimually from the one mile and a half 
 measured by us is only 1,237 tons. From these facts it is 
 evident at once that the erosive agencies tending to give a 
 V-shape to the mouth of the gorge could not have been in 
 operation much more than 10,000 years. To suppose they 
 had been at work for 30,000 or 40,000 years, as many still 
 try to do, involves an absurdly low rate of activity on the part 
 of the forces which have been constantly at work. 
 
 Something more also needs to be said about the significance 
 of the preglacial channel leading from the Whirlpool to St. 
 Davids. In the first place it should be noted that the mouth 
 of this gorge is very wide, being in fact nearly a mile in width, 
 thus indicating great age. In the second place, the depth of 
 the Whirlpool (1 50 feet), and the width of the head of the St. 
 Davids gorge (fully twice that of the Niagara gorge immedi- 
 ately above and below), point to an extreme age. It seems 
 altogether probable, indeed almost demonstr.able, that the 
 St.Davids' gorge had been worn back by a small stream formed 
 by the junction of two streams, one coming along the line of 
 the present gorge through the Whirlpool Rapids, and the 
 
550 THE ICE AGE IN NORTH AMERICA. 
 
 other coming from the north from a small water shed bounded 
 by the escarpment at Queenston. As the gorge both above 
 and below the Whirlpool is for some distance not more than 
 one-half the average width, it is probable that through these 
 spaces these small streams had worn in preglacial times 
 narrow gorges leading to the Whirlpool which had only to be 
 cleared of their glacial debris and somewhat enlarged by the 
 present stream when the cataract had receded to that point. 
 This would account both for the narrowness and the shallow- 
 ness of the gorge at these places. Whereas the water at the 
 Whirlpool is 150 feet deep and still more than that for two 
 miles below the Falls, it is only 35 feet deep in the Whirlpool 
 Rapids. Furthermore, at Fosters Flats, one mile below the 
 Whirlpool there is a projecting shelf extending into the gorge 
 from the western side nearly half its width, but into its upper 
 end on the side next to the main cliff there is the head of an 
 old narrow gorge opening up stream. This can hardly be 
 anything else than a remnant of the gorge supposed to have 
 been formed by a small northerly stream which found an 
 outlet through the Whirlpool. 
 
 We are bound to state, however, that Dr. Spencer main- 
 tains that the St. Davids outlet was not worn down to the 
 level of the present Whirlpool, and so is only a remnant of 
 erosion in some preceding era. But it is to be observed that 
 Dr. Spencer's borings to determine the depth of the glacial 
 filling in the St. Davids gorge, were considerably one side of 
 the center, while the measurement nearest the center was 
 abandoned before penetrating the rock below. The great 
 age of the gorge would imply a fully formed V-shape for it, 
 which would make the depth of the glacial filling to be small 
 near the sides. There is, therefore, no valid reason to doubt 
 that the St. Davids preglacial outlet was complete from the 
 Whirlpool at a depth equal to that of the present Niagara 
 gorge. 
 
 In view of all these considerations it seems evident that a 
 
THE DATE OF THE GLACIAL PERIOD. 
 
 551 
 
 considerable portion of the erosion of the Niagara gorge, 
 both above and below the Whirlpool, had been accomplished 
 before the glacial period, so that all the present stream had to 
 do was to clear of its unconsolidated till the portions of the 
 preglacial gorge which it occupied, and somewhat widen the 
 channel. 
 
 For future reference, if for nothing else, it is worth while 
 to introduce at this point a portion of our detailed study upon 
 the rate at which lateral erosion is proceeding through 
 atmospheric influences alone along the face of this gorge. 
 
 ^ec I 
 
 s.s'ec n 
 
 Fio. 141 — Sections showing the actuol rate of erosion along the sides of the Niagara 
 Gorge. 
 
 Section I was made 860 feet south of the tunnel at the north 
 end of the gorge, and the measurements were taken from the 
 outer rail of the track at points where a perpendicular excava- 
 
552 THE ICE AGE IN NORTH AMERICA. 
 
 tion in the Clinton Shale had been made fifty-five years be- 
 fore. The average of fifteen measurements made at twenty 
 foot intervals, showed that at the line of greatest erosion 
 fourteen feet of the Clinton Shale had fallen away during 
 that period; giving a rate of three inches a year. 
 
 Section II was made 6.317 feet from the tunnel in what was 
 a perpendicular excavation in the Niagara Shale fifty-five 
 years before. The average amount of greatest erosion along 
 this exposure was obtained by eleven measurements through- 
 out a distance of 1.185 feet, and proved to be fourteen and 
 eight tenths feet, or three and one quarter inches per year. 
 
 From these measurements it appears that the rate at which 
 the Clinton and Niagara shales crumble away over the whole 
 surface, through atmospheric agencies alone where unpro- 
 tected, is one and a half inches per year. 
 
 The question as to how much protection has been afforded 
 by the talus and the growth of vegetation cannot be defi- 
 nitely answered, but as our photograph on p. 544 shows the 
 Niagara shale has not been protected to any extent by a talus, 
 and but slightly by vegetation. It therefore seems entirely 
 within the bounds of probability that the erosion of the Nia- 
 gara Shale at the mouth of the gorge has proceeded at one- 
 seventh the rate at the exposures measured, which is about 
 one quarter of an inch per year, or one foot in forty-eight 
 years, which is the rate necessary to accomplish the whole 
 amount in 10,000 years. 
 
 A second typical place for the study of the recession of 
 post-glacial waterfalls is presented in the gorge of the 
 Mississippi River below the Falls of St. Anthony at Min- 
 neapolis. The problem here presented has been carefully 
 studied by Professor N. H. Winchell as follows.* 
 
 From the Falls of St. Anthony to Fort Snelling the gorge 
 between the rock-bluffs is somewhat less than a quarter of a 
 
 * "Geology of Minnesota," vol. ii, pp. 313-316, 340, 341. 
 
THE DATE OF THE GLACIAL PERIOD. 653 
 
 mile in width, and the rock has a freshly broken appearance, 
 the large fragments thrown down by the action of the water 
 on the easily crumbled sand-rock, as the falls have receded, 
 still existing in the talus along the bluffs. Throughout this 
 distance (about eight miles) the strata are horizontal, the thick- 
 ness of the drift-sheet overlying them nearly uniform, and all 
 other conditions, so far as they can be seen, that would affect 
 the rate of recession, seem to have exerted an unvarying in- 
 fluence. The inference is inevitable that the rate of recession 
 has been practically uniform between the two points named. 
 There is an aspect of age, and long weathering, presented by 
 the rock in the bluffs of the Mississippi below Fort Snelling. 
 It has a deeply changed color, a light-yellow, oxidized exterior, ' 
 which marks all old bluffs. The blue color is found at greater 
 depths from the surface than it is in the rock of the bluffs 
 above Fort Snelling. This stained condition also pervades the 
 lime-rock at the mouth of Bassett's Creek and at the quarries 
 in the ancient river-bluffs near the mouth of Shingle Creek, 
 on both sides of the river. Another notable difference between 
 the bluffs above Fort Snelling and those below consists in the 
 absence of caves, and subterranean streams entering the river, 
 above Port Snelling. Although the Trenton limestone exists 
 in full force about St. Paul, in the bluffs east and north of the 
 city, yet it had been cut through by some means prior to the 
 drift so as to allow the entrance and exit of streams of water 
 at levels below its horizon through the sandstone. None such 
 are found above Fort Snelling. The surface drainage is shed 
 by the limestone, and is precipitated over the brink of the 
 gorge, forming several beautiful cascades. When such streams 
 enter the river below Fort Snelling, they either enter some 
 subterranean passage and appear at the mouths of caverns in 
 the sandstone, or as springs in the drift along the talus, or 
 they find an ancient ravine down which they plunge, by a se- 
 ries of rapids over bowlders, to the river-level, rarely striking 
 either the lime-rock or the underlying sand-rock. Again, the 
 rock-bluffs at St. Paul, and everywhere below Fort Snelling, 
 are buried under the drift-sheet. Their angles are sometimes 
 seen jutting out from some wind-beaten corner, but nearly 
 everywhere thev are smoothed over by a mantle of drift and 
 
554 THE IGE AGE IN NORTH AMERICA. 
 
 loam. Even the immediate riTer-bank, where the lime-rock 
 should be intact, shows that it has been extensively disrupted 
 and its debris, often coarse and water-worn, in pieces from four 
 to ten feet long, is mixed with the coarse bowlders, gravel and 
 the drift, at the height of fifty to seventy-five feet above the 
 water-level, the heterogeneous mass lying on the worn upper 
 surface of the St. Peter sandstone. But above Fort Snelling 
 the upper edge of the lime-rock is intact all the way to the 
 falls, and shows a fresh-cut section. It is surmounted by a 
 continuous sheet of drift, which rises from the water-level in 
 one bluff coincident with the rock-cut. Its individual strata 
 show that they were cut by the recession of the falls in the 
 ' same manner as the strata of the rock. They do not conform 
 in their undulations to the outline of the rock, as if the gorge 
 were present when they were formed, as at St. Paul. There 
 is no spreading of loam over these cut edges, except such as 
 has fallen down from above at the time of their removal or 
 subsequent to it. At Fort Snelling, the direction of the Mis- 
 sissippi changes abruptly at a right angle. The change is 
 caused by entering the wide gorge which runs in that direc- 
 tion. This gorge is that in which the Minnesota runs, and is 
 out of proportion with the amount of water which it carries. 
 This valley continues in the same direction, and with the same 
 width, beyond the confluence of the Mississippi, but takes the 
 name of the latter stream. At one mile below the mouth of 
 the Minnesota it is a mile and a half wide. 
 
 These features of greater age, pertaining to the bluffs of 
 the Mississippi below Fort Snelling, are seen in the old rock- 
 bluffs of the river above the mouth of Bassett's Creek as far as 
 to Shingle Creek. The rock there is deeply changed in color, 
 and is hid by the drift, and the bluffs, as left by the more an- 
 cient river, are far apart, the old gorge being three or four 
 times as wide as that between the falls and Fort Snelling. 
 These rock-bluffs, consisting of the same limestone as that 
 which at the falls is below the water, here rise from thirty to 
 forty feet above the river, and are buried under loam, or under 
 drift and loam. This part of the old valley continues south- 
 wardly, by way of Bassett's Creek (below its last turn), across 
 the western suburbs of Minneapolis, through the valleys occu- 
 
THE DATE OF THE aLACIAL PhRIOD. 
 
 555 
 
 pied by Lakes Calhouu and Harriet, and joins the Minnesota 
 at some point above Fort Snelling, the precise locality being 
 
 ^ALLS IN 1B30 
 TAILS IK1680 
 
 Fia. 142.— Map of Mississippi Kiver from Fort Snelling to Minneapolis and the vicinity, 
 sbowing tne extent of the recession of the Falls of St. Anthony since the great Ice 
 age. ifotice the greater breadth of the valley of the Minnesota Biver as described in 
 the text, 
 
 hid by a subsequent deposit of drift. It was cut down into 
 the St. Peter sandstone over one hundred feet at least, as 
 shown by the well at the Sumner school-house, and about two 
 
556 THE ICE AGE IN NORTH AMERICA. 
 
 hundred and seyenty-five feet, as shown by the deep well at the 
 Lakewood Cemetery. This would show that probably the an- 
 cient valley of the Minnesota where it passes Fort Snelling, 
 and all the way through Ramsey county and below, has been 
 filled more than two hundred feet by drift that originated 
 since the excavation of the gorge. This supposition is borne 
 out by all borings that have been made between the rock-bluffs 
 at lower points, as at West St. Paul and at Lake City. Such 
 excavation is not found in the river-gorge between Fort Snel- 
 ling and the Falls of St. Anthony ; but, below the water, are 
 found, first, some large fragments of limestone, and some bowl- 
 ders of foreign origin, the whole being generally less than 
 twenty-five feet in thickness, and below that the undisturbed 
 St. Peter sand-rock is found, suitable for the foundation of 
 piers for bridges. 
 
 These facts warrant the conclusion that that part of the 
 Mississippi gorge above Fort Snelling has been excavated by 
 the recession of the falls since the last general drift movement, 
 and that prior to that event there was a gorge which passed 
 from the present channel of the Mississippi at the mouth of 
 Bassett's Creek southward to the great gorge of the Minnesota 
 at some place above Fort Snelling. It is probahle that this 
 gorge was then occupied by waters that drained from the 
 northern part of the State, and had existed through many ages, 
 dating back to pre-Cretaceous times. It seems to have been 
 filled first by a blue till, or partly filled, and to have remained 
 free for the passage of the Mississippi during the on-coming of 
 the Glacial epoch, till the advent of the ice of the last Glacial 
 epoch, when morainic accumulations so choked it that the 
 water of- the river was driven out and compelled to seek an- 
 other passage to the Minnesota. When this last event took 
 place, the Falls of St. Anthony probably began at Fort Snel- 
 ling, the water being precipitated over the rock-blufE of the 
 pre-existing old gorge, unless the whole valley was too deeply 
 buried under water. Whether this was at the beginning or at 
 the acme of cold, or at the recession of the ice, is a question 
 which may well be considered, but at this time the only point 
 that is claimed is that it was not earlier than the beginning of 
 the last Glacial epoch, and was probably near the acme of cold. 
 
THE DATE OF TEE GLACIAL PERIOD. 557 
 
 Having thus established the post-glacial origin of the 
 gorge below the Falls of St. Anthony, the next point was to 
 determine the rate at which the recession has been proceed- 
 ing. Fortunately, upon this point an abundance of evidence 
 is available. The falls were first visited and described as 
 early a& 1680 by the Jesuit missionary Hennepin. His de- 
 scription is found in the Amsterdam edition of his works, 
 printed in 1704. The falls were again visited in 1766, eigh- 
 ty six years later, by Carver, another Jesuit missionary. In 
 addition to his description this traveler made a sketch of the 
 falls, which was engraved to accompany his travels, published 
 in London in 1778. Subsequent travelers who describe it 
 are Major Z. M. Pike, in 1805 ; Major Stephen S. Long, in 
 1817 ; Schoolcraft, in 1820 ; Professor William Keating and 
 Mr. Beltrami, Kev. W. T. Boutwell and Schoolcraft, in 1832; 
 and Mr. G. W. Featherstonhaugh, in 1835. In addition vari- 
 ous artists have gathered descriptions of the falls as they ap- 
 peared in 1842, 1848, 1853, and in 1857, and daguerreotypes 
 were taken in 1851 ; while in 1853, before the erection of saw- 
 mills, Mr. J. W. Bond gave a careful description of the falls 
 as they then existed, and numerous living witnesses fix their 
 position in 1856, when artificial changes were introduced, 
 which so modified the rate of recession as to disturb further 
 calculation. The period, then, during which evidence is avail- 
 able for calculation is that between Hennepin's visit in 1680 
 and the year 1856 — one hundred and seventy-six years. The 
 deseriptiouB are so minute that Professor Winchell is able to 
 fix beyond doubt the various stages of recession between 
 these dates. 
 
 In 1680 the falls were near the south end of Hennepin 
 and Spirit Islands, not far above the present Tenth Ave- 
 nne Bridge. In 1766, at the time of Carver's visit, the falls 
 had receded about four hundred and twelve feet, and were at 
 Carver's Island. In 1856 the west falls were abont five hun- 
 dred feet below their present position, which is now made sta- 
 tionary by artificial means. According to Professor Winchell, 
 the recession from 1680 to 1766, between Hennepin and 
 
558 THE ICE AGE IN NORTH AMERICA. 
 
 Carver, was four hundred and twelve feet ; and between 1766 
 and 1856, six hundred feet, making a total between 1680 and 
 1856, of one thousand and eighteen feet. " These give re- 
 spectively the rates 4-79, 6-73, and 5-08 feet per year, and for 
 the corresponding periods necessary for the recession of the 
 falls from Fort Snelling (a distance of a trifle over eight 
 miles) 8,819 years, 6,276 years, and 8,315 years. The aver- 
 age of these three results is 7,803 years." 
 
 Professor Winchell then proceeds to discuss the possible 
 elements of error in this calculation : 
 
 1. That arising from difference in the volume of the 
 river. The terraces already described in the chapter on 
 " Preglacial Drainage," as characterizing both the Minnesota 
 River and the upper Mississippi, reveal the existence of 
 enormous floods during the closing stages of the Glacial pe- 
 riod. Indeed, these floods in the Minnesota River were so 
 high as to fill it up to the level of the lime-rock at Fort Snel- 
 ling, about one hundred feet. During the existence of this 
 high water, therefore, there could have been no cataract at 
 Fort Snelling or farther up the Mississippi. The Falls of 
 St. Anthony could have begun only after the floods of the 
 Minnesota began to shrink so as to uncover the lime-rock at 
 Fort Snelling. 
 
 2. Difference in the height of the falls at various points 
 from Fort Snelling up to its present position. This is shown 
 to be comparatively insignificant, so that it can be left out of 
 the account. 
 
 3. The stage of the Glacial period when the recession 
 began. Upon this we quote again at length : 
 
 This point has already been considered in the possible va- 
 riations in the volume of the river. It is probable that the 
 Mississippi, in diminutive form, began to flow in its new 
 channel at the acme of the cold,* since the moraine of the sec- 
 ond Glacial epoch runs across the country, approximately 
 through this region, and since it would have remained in its 
 
 * See map of Minnesota in next chapter (Fig 181). 
 
THE DATE OF THE GLACIAL PERIOD. 559 
 
 preglacial channel till it was driven out by the encroaching 
 moraine. It was the easier removed from its old channel by 
 reason of its reduction in volume. When it began its course 
 in its new channel, it flowed over a broad pla.in of gravel and 
 sand, the then latest accumulations of glacial torrents. This 
 plain of gravel and sand extended throughout the adjoining 
 space now occupied by such drift deposits. The same kind of 
 deposits filled the whole Minnesota Valley, from side to side, 
 and rose as high as the plains back of Port Snelling. The 
 river, being comparatively small, had but little effect on these 
 deposits. If it excavated any channel, the torrents from the 
 ever-present glacier-ice filled them at once — indeed, it exca- 
 vated, it refilled, as it was glacier-born. It was on the retire- 
 ment of ice, bringing a greater drainage area into contribution 
 to swell the main streams at this latitude, that these rivers 
 began to deposit the fine loam-sand which covers the coarse 
 gravel and sand of these terraces. It was still later, when 
 the rivers were shrunk, by the partial or complete with- 
 drawal of the glaciers from their remote sources, that they 
 began to excavate through the loam and the gravel and 
 sand and finally entered on the slow erosion of rock-gorges. 
 Thus it appears that the date from which the recession of 
 the falls must be reckoned was after the outlet of Lake 
 Agassiz had been opened toward the north, one of the last 
 acts of the Ice age. . . . 
 
 Finally, if all the supposed irregularities be allowed their 
 full force, and all the elements of doubt be admitted, their 
 combined effect would not, at the most, more than slightly 
 modify the result. And even if it should double the first result, 
 or should reduce it to one half, the chief value of the calcula- 
 tion is not impaired. That consists in showing the lateness of 
 the last Glacial epoch compared with the enormous time that 
 has sometimes been supposed to have elapsed since its de- 
 parture. 
 
 If the occurrence of our winter in aphelion, caused by the 
 precession of the equinoxes and the revolution of the line of 
 the apsides, about eleven thousand three hundred years ago, 
 was the cause of our last Glacial period, it follows that it re- 
 quired about thirty-five hundred years for the withdrawal 
 
560 TEE ICE AGE IN NORTH AMERICA. 
 
 of the ice-margin from the vicinity of Fort Snelling to that 
 place where the discharge of Lake Agassiz was opened to- 
 ward the north, reducing the Minnesota to nearly its present 
 size. This change must have given prominence and erosive 
 effect to the waterfall at Fort Snelling, if it did not give it 
 birth. 
 
 These calculations concerniDg the age of Niagara and 
 the Falls of St. Anthony are amply sustained by the study 
 of various minor waterfalls and gorges in Ohio to which I 
 have myself given special attention. For example, at Elyria, 
 twenty-five miles west of Cleveland, Black Eiver plunges 
 over the outcropping Waverly sandstone, and flows onward 
 to the lake through a wide valley in the Erie shale, which 
 was doubtless preglacial, though no buried channel above 
 has yet been discovered. The gorge below the falls, which 
 has been eroded since glacial times, and which approximately 
 represents the work done by Black River during that time, 
 is only a trifle over two thousand feet long. The water 
 flowing over the falls represents the drainage of about four 
 hundred square miles, and the sandstone which forms the 
 precipice over which the water plunges is underlaid by soft 
 shale very favorable to rapid erosion. In March, 1871, a 
 mass of rock fell which was so large that the concussion 
 shook the whole town and produced the semblance of an 
 earthquake. With the present forces in operation at this 
 point, it would seem incredible that the average rate of re- 
 cession should not be considerably more than one foot in 
 fifty years. Yet thus infinitesimal would be the rate if one 
 hundred thousand years must be allowed for the time separat- 
 ing us from the birth of the present waterfall at Elyria. 
 The shortness of this and other similar gorges in that region 
 points to a great reduction of the prevalent estimates of 
 glacial chronology. 
 
 Another interesting confirmation of this moderate esti- 
 mate is to be found in Paint Creek Valley, in the southern 
 part of Ohio, to which attention was directed in a previous 
 chapter. As was discovered by Professor Orton several years 
 
THE DATE OF THE GLACIAL PERIOD. 561 
 
 ago, this stream, a few miles above its junction ■with, the 
 Scioto, at Chillicothe, abandoned its preglacial valley in a 
 most singular manner.* The preglacial valley of Paint 
 Creek for about twenty miles above its junction with the 
 Scioto runs in a northeast direction from the town of Bain- 
 bridge. The valley is nearly a mile wide at the bottom, and 
 about five hundred feet below the general level. But the pres- 
 ent stream, after it has abandoned this old valley, occupies 
 for two or three miles a narrow gorge not over five hundred 
 feet wide, cutting directly through the table-land, 9iid re- 
 entering the old valley considerably lower down in its course. 
 The only satisfactory explanation of this is found in a study 
 of the local glacial phenomena. The lower or northeastern 
 part of this preglacial valley is exactly on the line of the gla- 
 cial boundary, and was for a certain period obstructed by the 
 most advanced portions of the glacier, which dammed up 
 the water and raised it to a level at which it would be forced 
 in front of the ice across a tongue of the table-land, thus 
 eroding the present channel.f 
 
 This portion of the channel, as already indicated, is about 
 three miles long, from three hundred to five hundred 
 feet deep, five hundred feet wide at the top, and two hun- 
 dred at the bottom. The walls near the top consist of fifty 
 or sixty feet of Waverly sandstone, while aU below is a soft 
 shale crumbling very readily. The question in glacial chro- 
 nology is to find the age of this gorge, which is clearly post- 
 glacial. The true solution of the problem comes from a 
 study of one of the lateral gorges formed by a small tributary 
 entering the main gorge midway from the south. This 
 tributary, though dry a portion of the year, is at other times 
 a raging torrent, and drains an area of two or three square 
 miles. Yet in the soft shale, so favorable for rapid erosion, 
 it has worn a gorge less than six hundred feet long, but hav- 
 ing a mouth of nearly the same width where it joins the 
 
 * " Geological Survey of Ohio," vol. ii, p. 653. 
 f Sec map, p. 373. 
 
562 
 
 THE ICE AGE IX NORTH AMERICA. 
 
 main channel. It can scarcely be possible that these forces 
 have been in operation in their present position for many 
 
 thousand years ; for, ac- 
 cording to the testin.ony 
 of Mr. Long, who has 
 been a resident upon the 
 ground for fifty years, 
 and has definite data for 
 calculation, this tributary 
 creek has worn back sev- 
 eral feet since his re- 
 membrance. If the rate 
 of recession for this trib- 
 utary gorge were as little 
 as one foot in twenty 
 vears, only twelve thou- 
 sand years would be re- 
 quired for the accom- 
 plishment of the work 
 done. If we should go 
 back to the period as- 
 signed by Mr. CroU's the- 
 ory to find the Glacial period, the rate of recession would 
 be incredibly slow, and far below what is pretty certainly the 
 rate at the present time. 
 
 An extreme length was at one time given to the intergla- 
 cial episodes by attributing to interglacial time much erosion 
 that was preglacial. For example Professor Chamberlin in 
 his early publications regarded the gorge of the Ohio and the 
 Alleghen}' as well as those of the Delaware and the Lehigh as 
 the work of interglacial erosion. If this were the case, the 
 interglacial episodes must have been of enormous extent, for 
 these are rock gorges ot great leng-th and 200 or 300 feet in 
 depth. 
 
 Subsequent investigations, however, showed that the most 
 of this erosion was preglacial rather than interglacial. At 
 Warren, Pennsylvania, on the Allegheny River, as already 
 
 Fig. 143.— LtU-al view uf an old luiLrlnriatcfi runii- 
 try, showing tht- form assnmcd hv the emi- 
 nences when erosion has proceeded to a great 
 extent. (United States Geological SarVey.) 
 (Chamberlin.) 
 
THE DATE OF THE GLACIAL PERIOD. 
 
 563 
 
 detailed, the upper gravel terraces which Professor Charober- 
 lin had separated from the lower ones by this enormous 
 interval, were found to 
 be continuous, showing 
 that thej' belonged to 
 the same period, while 
 deeply buried gorges filled 
 with glacial debris of 
 Kansan age opened into 
 the main channel from 
 the south. As already 
 remarked, also, the high- 
 level terraces of the 
 Monongahela were not, 
 as Professor Chamberlin 
 maintained, ordinary 
 river flood-plains, but 
 shore lines of a glacial 
 lake produced by dam- 
 mingupof theoutletinto 
 Lake Erie, byway of the Mahoning and Grand River valleys. 
 The most, therefore, that can be made of the interglacial 
 time from the erosion of the Ohio River gorge is that needed 
 for the wearing down of the cols between the branches of the 
 various streams that were flowing north and were dammed up 
 by the advancing ice-sheet. As already shown it was the 
 junction of these upper branches which formed the present 
 tortuous channel of the Ohio River. The gorge of the Dela- 
 ware was proven to be preglacial by the investigations of 
 Professor E. H. Williams, which brought to light the fact that 
 at Bethlehem, Pa., the present Lehigh River flows over a 
 bed of glacial debris filling an old channel which is 120 feet 
 deep, and this in a region reached only by the very earliest 
 ice invasion. The rock gorge of the Delaware into which the 
 Lehigh empties must, therefore, be wholly preglacial. 
 
 Fig. 144 — A country, in contrast with that on the 
 opposite page, in which the dralnn.ge has been 
 d isturbed by glacial deposits and the atreams are 
 beginning to wear new channels. (ChamberUn.) 
 
564 
 
 THE ICE AGE IN NORTH AMERICA. 
 
 Another most instructive illustration of the extent of 
 preglacial erosion is found west of Keokuk, Iowa,* where there 
 is a buried channel of great width now filled with glacial dibris 
 while the river at Keokuk flows over a rock bottom and 
 through a comparatively narrow channel. 
 
 ^■^j'^yy/yy-y^ 
 
 
 Fia. 145 — Meanderlngs of Plum Creek through 5000 feet of ita trough. 
 
 - 2tFf 
 
 Sl/t. 
 
 ' 10 F>. 
 
 ^ 17 ft 
 
 Fig. 146 — Cross section of the new course of Plum Creek, showing Its original width and 
 Its enlargement In twelve years. 
 
 Another means of measuring thhe amount of erosion 
 since the Glacial period is found in post-glacial river-valleys 
 by estimating the amount of material which has been car- 
 ried out by the present streams from the glacial deposit 
 itself. 
 
 Professor Hicks, of Granville, Ohio, reported in 1884,t 
 some important results of such an investigation in the valley 
 of Raccoon Creek, Licking county, near the glacial border. 
 Thi present flood plain of this creek is now bordered on 
 either side by gravel terraces about fifty feet high, which are 
 
 * See cut on page 310. 
 
 t "Baptist Quarterly'; for July, 1884. See also Fig. 99, p. 324. 
 
THE DATE OP THE GLACIAL PERIOD. 565 
 
 evidently the remains of a modified glacial deposit formerly 
 filling the wliole valley to that height. Since the Glacial 
 period the present stream has been occupied with the task of 
 slowly removing this material. The number of cubic yards 
 which it has already carried away can be approximately esti- 
 mated. The rate of removal is more difiicult to determine. 
 Assuming the rate to be the same per cubic foot of water as 
 that which is transported by the Mississippi River past New 
 Orleans, which doubtless is far too small, the time required 
 would be, according to the calculation of Professor Hicks, 
 less than fifteen thousand years. 
 
 I have been able to make a more definite calculation in 
 connection with Plum Creek, in Oberlin, Ohio. The situa- 
 tion is peculiarly favorable both on account of its relation to 
 the glacial shore lines around Lake Erie, and of its freedom 
 from disturbing obstacles. The section of the Creek Valley 
 from which the facts are gathered lies ten miles south of the 
 present shore of Lake Erie, and 250 feet above the lake level. 
 It is about five miles south of the highest of the lake ridges, 
 and fifty feet higher than the upper ridge. Its course is 
 wholly in glacial till with no rock bottom anywhere in its 
 course. The average gradient of the stream is twelve feet 
 to the mile, falling 100 feet in eight miles. It is evident that 
 the stream did not begin the erosion of its present trough 
 until the ice-sheet had retreated from the water-shed on the 
 south and had uncovered the outlet of the glacial lake at 
 Fort Wayne, which determined the level of water on whose 
 shores the upper ridge was thrown up by the waves. The 
 Plum Creek trough is therefore older than the Niagara gorge 
 by the length of time that was required for the retreat of the 
 ice-sheet from the south shore of Lake Erietothe Adirondack 
 Mountains, a distance of 200 or 300 miles; for, as already said, 
 Niagara did not begin its work until the Mohawk Valley, 
 south of the Adirondack Mountains was free from ice. 
 
 Now, in 1895, a reservoir was constructed in the village 
 occupying the whole width of the trough of the creek, and 
 
566 THE ICE AGE IN NORTH AMERICA. 
 
 compelling the engineers to open a new channel across an 
 undisturbed neck of the original glacial till. The section of 
 this chosen for observation was 500 feet long, and at first 
 consisted of a ditch twenty-one feet wide at the top, and 
 ten at the bottom, with an average depth of eleven feet, 
 though on the south side it rose to a height of twenty feet 
 above the bottom. But, after a lapse of twelve years (in 
 1907), the stream had enlarged the ditch to a width of fifty- 
 one feet at the top, and of seventeen feet at the bottom, giving 
 an average width of thirty-four feet compared with the original 
 of fifteen and one-half feet. A simple mathematical calcula- 
 tion shows, therefore, that in twelve years this stream had 
 removed from a 500-foot section whose banks were exposed 
 to the direct action of the current on both sides, 101,750 
 cubic feet of solid matter, or, 8,450 cubic feet per annum. 
 
 To get a more perfect basis of comparison, measurements 
 were taken of a section 5,000 feet long belowthe village, where 
 the original conditions had been undisturbed. In this sec- 
 tion the eroded trough averaged 400 feet in width and seven- 
 teen feet in depth, and this entirely in glacial till such as 
 characterizes the whole valley. The total amount, therefore, 
 of w^ork accomplished, by the stream in this section since the 
 present line of drainage was opened was the removal of 
 34,000,000 cubic feet of till. 
 
 To obtain a still more approximate basis for calculation 
 it was necessary to measure the length of the sections of the 
 edge of the trough where the stream impinges directly against 
 the bluff and so is eroding under conditions similar to those 
 in the cut-off at the reservoir. Upon doiug this it was 
 found that these exposed sections amounted to 1,600 feet in 
 length, which is 600 feet more than that of both sides of the 
 cut-off. The annual erosion, therefore, in the 5,000-foot 
 section is now one and six-teuths greater than in the cut-off, 
 making 13,568 cubic feet of material per year. At this rate 
 the 34,000,000 feet of material from the 5,000-foot section 
 
THE BATE OF THE GLACIAL PERIOD. 667 
 
 would be removed in 2,505 years; a result so incredible that 
 we are called to examine more closely into the various con- 
 ditions affecting the problem, some of which would tend to 
 retard the eroding action of the stream, and some to accel- 
 erate it. 
 
 Of the retarding influences the most conspicuous is the 
 former existence of a dense forest of large trees covering the 
 whole basin. It is scarcely possible, however, that the rate 
 would be reduced from this cause lower than to one-tenth of 
 that of the present time, which, if there were no counteract- 
 ing causes, would extend the time to 25,000 years. 
 
 But, on the other hand, it is evident that the rate of erosion 
 in the main trough is, at its present width, at a minimum. 
 For, as the width of the trough has enlarged, it has taken the 
 stream a longer and longer time to swing from side to side in 
 its meanderings. At the outset the stream acted through the 
 entire length on both sides as it now does in the cut-off, and 
 when the width of the trough was half what it is now, the 
 erosion was twice as fast. 
 
 It is safe to say, therefore, that the average rate during 
 the forested condition would be twice what we have allowed. 
 This would reduce the time to 12,500 years, which cannot be 
 far from a correct estimate. For, in addition to the early 
 constriction of the channel in increasing the rate, it should 
 be kept in mind that on the first withdrawal of the ice there 
 was no forest to retard the action of the stream. Further- 
 more, it is altogether probable that there was a much greater 
 precipitation over the basin of the creek while the ice lingered 
 over the area immediatelj' to the northward, and this would 
 increase the rate of erosion. 
 
 It has been necessary to enter thus fully into details con- 
 cerning one instance in order to get the force of the cumula- 
 tive argument from the innumerable similar instances which 
 present themselves all over the area in which the natural 
 drainage is towards the front of the ice-sheet. Present 
 
568 THE ICE AGE IN NORTH AMERICA. 
 
 eroding forces cannot have been at work over this region for 
 much more than 10,000 years, and this is some time previous 
 to the beginning of the work of the present Niagara River. 
 Another class of facts which seems to set moderate limits 
 to glacial chronology relates to the amount of superficial ero- 
 sion of glacial deposits of various sorts, and the extent to 
 which the rocks have been disintegrated since that period. 
 • President T. C. Chamberlin, when State geologist of 
 Wisconsin, remarked that no sensible denudation had taken 
 place there since glacial times.* Even Mr. CroU expresses 
 surprise at the small amount of erosion which has taken 
 place since the kames of Scotland were deposited. Both in 
 Europe and in America these peculiar relics of the Glacial 
 period retain a sharpness of outline which it is difficult to be- 
 lieve could have survived the protracted period of one hun- 
 dred thousand or even of forty thousand years, according to 
 Hitchcock's reckoning. When, also, one considers the chemi- 
 cal agencies at work to decompose the rocks wherever un- 
 protected by a covering of till, the freshness of the glaciated 
 surfaces never ceases to be a cause of astonishment. 
 
 Dr. Geo. F. Becker, of the United St.ates Geological Sur- 
 vey, bears striking testimony to the freshness of the glaciated 
 surfaces of the rocks in the mountains of California on the 
 Pacific Coast. He writes: 
 
 "No one, who has examined the glaciated regions of "the 
 Sierra can doubt that the great mass of the ice disappeared 
 at a very recent period. The immense areas of polished 
 surfaces fully exposed to the severe climate of say from 
 7,000 to 12,000 feet altitude, the insensible erosion of streams 
 running over glaciated rocks, and the freshness of erratic 
 bowlders are suflicient evidence of this. There is also evi- 
 dence that the glaciation began at no very distant geologic 
 date. As Professor Whitney pointed out, glaciation is the 
 last important geological phenomenon and succeeded the 
 great lava flows. 
 
 Geology of Wisconsin," vol. ii, p. 632. 
 
THE DATE OF THE GLACIAL PERIOD. 569 
 
 There is also much evidence that erosion has been trifling 
 since the commencement of glaciation, excepting under 
 pecuUar circumstances, east of the range, for example, at 
 Virginia City; and sites which there is every reason to sup- 
 pose preglacial have scarcely suffered at all from erosion, 
 so that depressions down which water runs at every shower 
 are not yet marked with water-co\irses, while older rocks, 
 even of tertiary age and close by, are deeply carved. The 
 rainfall at Virginia City is, to be sure, only about ten inches, 
 so that rock would erode only say one-third as fast as on the 
 California coast; but even when full allowance is made for 
 this difference, it is clear that these andesites must be much 
 younger than the commencement of glaciation in the north- 
 eastern portion of the continent as usually estimated. So, 
 too, the andesites near Clear Lake, in California, though 
 beyond a doubt preglacial, have suffered little erosion, and 
 one of the masses, Mount Konocti (or Uncle Sam), has 
 nearly as characteristic a volcanic form as Mount Vesuvius."* 
 
 Dr. Bellt also writes as follows: "On Portland promontory, 
 on the east coast of Hudson'sBay, in latitude 58", and south- 
 ward, the high, rocky hills are completely glaciated and bare. 
 The strisB are as fresh looking as if the ice had left them 
 only yesterday. When the sun bursts upon these hills 
 after they have been wet by the rain, they glitter and shine 
 like the tinned roofs of the city of Montreal." Again, Pro- 
 fessor MacounJ writes of the red Laurentian gneiss in the 
 vicinity of Fort Chippewayan, at the west end of Lake Atha- 
 basca: "The rocks around the fort are all smoothed and 
 polished by ice action. When the sun shines they glisten 
 like so much glass, and a person walking upon them is in 
 constant danger of falling." 
 
 • "Bulletin of the Geological Society of America," vol. ii, pp. 
 196, 197. To the same effect see the testimony of Prof. I. C. Russell 
 and Prof. Gilbert, below p. 609. 
 
 t "Bulletin of the Geological Society of America," vol. i, p. 308. 
 
 t "Geological Survey of Canada, Report of Progress," 1875-1876, 
 p. 90. 
 
570 THE ICE AGE IN NORTH AMERICA. 
 
 "Likewise, concerning the glaciation of Europe, we find 
 that in Wales and in Yorkshire, England, the amount of 
 denudation of limestone rocks on which bowlders lie has 
 been regarded by Mr. Mackintosh* as a proof that a period 
 of not more than six thousand years has elapsed since the 
 bowlders were left in their positions. The vertical extent 
 of this denudation, averaging about six inches, is nearly the 
 same with that observed in the southwest part of the Province 
 of Quebec by Sir William Logan and Dr. Robert Bell, where ' 
 veins of quartz marked with glacial striae stand out at 
 various heights not exceeding one foot above the weathered 
 surface of the enclosing limestone. 
 
 As illustratiag how little we know about the causes which 
 produce the variations in snow fall, even from year to year, 
 and render it impossible to form trustworthy a priori opinions 
 concerning the proximity of the causes which are capable of 
 producing glacial conditions, Mr. Becker writes that in 
 1890 the "snowfall in the Sierra was exceptionally large, 
 about two and one-fourth times the average precipitation 
 having fallen. Much of this snow remained unmelted through 
 the season, and when I left the mountains, on October 1, 
 there were still thousands of snowbanks where in ordinary 
 seasons none remains even far earlier in the season. Many 
 of these banks were also of great depths, say 100 feet, more 
 or less. It is clear, therefore, that were this and succeeding 
 winters to be as wet as the last, the range would show glaciers 
 in great numbers, much as the Alps now do; in short, tho 
 glacial period of the Sierra would recur in a moderate way. 
 Now, no one doubts that there was some cause for the unusual 
 snowfall of 1889-90 but no one has any suspicion what it 
 was. No sensible change in cosmical or terrestrial condi- 
 tions has occurred, the weather of the world at large was not 
 remarkable, and, excepting as to precipitation, the year was 
 not extraordinary even in California." 
 
 * "Quarterly Journal of the Geological Society," vol. xxxix, pp. 
 67-69; vol. xlii, pp. 527-539. 
 
THE DATE OF THE GLACIAL PERIOD. 571 
 
 Again evidence comes from the extent to which lakes, 
 dating from the Glacial period, have been filled with sedi- 
 ment. Little reflection is required to make it evident that 
 our present lake-basins could not always have existed ; for, 
 except where counteracting agencies are at work, the " wash " 
 of the hills will, in due time, fill to the brim all inclosed 
 areas of depression. Mr. Upham, of the Minnesota Geo- 
 logical Survey, expresses surprise at the small extent to 
 which the numerous lakes of that State have been filled 
 with the sediment continually washing into them. " The 
 lapse of time since the Ice age has been insufiicient for rains 
 and streams to fill these basins with sediment, or to cut out- 
 lets low enough to drain them, though in many instances we 
 can see such changes slowly going forward." * 
 
 Dr. E. Andrews, of Chicago, has made calculations, de- 
 serving of more attention than they have had, concerning the 
 rate at which the waters of Lake Michigan are eating into 
 the shores, and washing the sediment into deeper water or 
 toward the southern end of the lake.f The United States 
 Coast Survey have carefully sounded the lake in all its parts, 
 and have ascertained the width of the area of shallow water 
 extending inward from the shores. It is well known that 
 waves are limited in their downward action, so that there 
 will be a surrounding shelf, or shoulder of shallow water, in 
 cases where the waves of a deep lake are eroding its banks. 
 This fringe of shallow water encircling Lake Michigan is 
 only a few miles wide ; and from such data as have been gath- 
 ered, the average rate of erosion is found to be as much as 
 five or six feet per annum ; which would indicate that the 
 lake-basins had not been in existence more than seventy-five 
 hundred years. 
 
 Leaving these more indefinite and in many respects un- 
 satisfactory efforts to estimate the age of lake-basins, we 
 may get some assistance in approximating to a correct chro- 
 
 * " Minnesota Geological Report " for 1879, p. 73. 
 
 f "American Journal of Science," vol. xcviii, 1869, pp. 172 et seq. 
 
572 THE ICE AGE IK NOBTH AMERICA. 
 
 nology of the Glacial age by studying tlie smaller kettle-holes 
 which constitute so marked a feature in the kames and 
 moraines of the glaciated region. As already shown, the most 
 satisfactory explanation of these curious depressions is, that 
 they mark places where masses of ice were buried in the 
 delris of sand and gravel brought down by the streams of 
 the decaying glacier ; and where, upon the melting of the 
 buried ice, a cone-shaped depression was left with sides as 
 steeply inclined as the nature of the soil would permit. At 
 any rate, tliere can be no question that the kettle-holes were 
 formed during the closing stages of the Glacial period. 
 
 As typical of numberless others we present the facts 
 concerning a kettle-hole near Pomp's Pond in Andover, 
 Mass.* 
 
 Pomp's Pond is itself a moraine basin about a quarter of a 
 mile in diameter, and but slightly above the level of the Shaw- 
 shin River, into which it empties. Upon its north side is an 
 accumulation of gravel and sand, with pebbles intermingled, 
 in which there are several of the smaller characteristic bowl- 
 shaped depressions of which we have spoken. Their appear- 
 ance is much like that of volcanic craters. You ascend a 
 shai"p acclivity from every side to a rim of gravel, and then 
 descend as rapidly into the bowl-shaped or crater-like depres- 
 sion. A section carried across will present the idea. 
 
 Pomp^B 
 
 Fig. 147.— Section of kettle-hole near Pomp's Pond. Andover, Massachusetts. (See text.) 
 (For general view of the sitnation, see Fig. 101, p. 338). 
 
 From the level of the pond, and two or three rods from the 
 edge, you begin to ascend at an average rate of about one foot 
 in three, till the south side of the rim is reached, at a height 
 of fifty-two and five tenths feet above the pond, {a) (This rim 
 is not, however, of a uniform height. On the east side it rises 
 
 * .1 here transfer a few paragraphs from my " Studies in Science and Re- 
 ligion." 
 
THE DATE OF THE GLACIAL PERIOD. 573 
 
 into a pyramid serenty-seven feet high.) (5) Then, descending 
 fifty and five tenths feet vertically, you are carried one hundred 
 and thirty-eight feet horizontally, reaching at that point the 
 edge of a circular mass of peat which is ninety-six feet in di- 
 ameter, (c) From the opposite side the ascent of the northern 
 rim begins, and you descend from its top to the valley, repeat- 
 ing almost exactly the first descent from the pond. The dis- 
 tance from rim to rim, or the diameter is three hundred and 
 eighty feet. 
 
 It is evident that since the first formation of this crater- 
 shaped depression no material can have reached the bottom, 
 except from three sources : 1. The wash from the side ; 2. 
 The decay of vegetation which grew within the circumference 
 of the rim ; 3. The material brought by the winds. It is 
 equally evident that what is once in can not get out. 
 
 Dust, leaves, and twigs carried by the winds inevitably 
 lodge in such depressions more thickly than in other places, 
 since the atmosphere in such hollows is comparatively quiet. 
 For the same reason the surrounding trees as they are blown 
 down are more likely to fall toward the center of the kettle- 
 hole ; and the ashy material which their roots abstract from 
 the sides of the depression is no insignificant factor in the 
 problem. 
 
 'Sow, from the angle of the declivity, the original depth of 
 the depression can be approximately estimated. If the angle 
 be still the same as at first, the first three terms of the propor- 
 tion would be 138 : 50*5 : : 48 : 17|^f, making the original 
 depth below the present surface of the peat a trifle over 17 -5 
 feet. If, however, we suppose the original slant to have been 
 steeper and the rim higher, we can still see that there must 
 have been a limit to the depth. Suppose the rim to have been 
 one third higher and the slant one third steeper, we then 
 should have in round numbers the proportion 138 : 68 : : 48 : 
 23^, making the original depth of the depression nearly 
 twenty -four feet below the present surface of the peat. From 
 the nature of the material it is impossible that the depth could 
 originally have much exceeded that amount. 
 
 Accepting this conclusion, the problem is, to determine the 
 time it would require the agencies mentioned above to fill the 
 
574 THE IGE AGE IN NORTH AMERICA. 
 
 bottom of this bowl to a depth of twenty-four feet — a cone 
 ninety-six feet in diameter at the base and twenty-four feet to 
 the apex — which would be equal to a deposit of only eight feet 
 over the present surface of the bottom. The question is. 
 Could this have stood with so little change for eighty thousand 
 years ; or even for forty thousand years, if we were to accept 
 Professor Charles H. Hitchcock's estimate of the prolongation 
 of the effects of Croll's period ? * Is not the supposition of 
 ten thousand years sufficiently extravagant ? If the close of 
 the great Glacial period be so far back as Mr. Croll estimates, 
 we must believe that sediment would accumulate, in the situ- 
 ation above described, over the surface of the present peat-bog, 
 at the rate of only one inch in a thousand years ; while, if 
 we put the close of this period back ten thousand years, the 
 rate of accumulation would seem to be as slow as our imagina- 
 tion can well comprehend. One hundred inches, which is 
 little more than eight feet, divided into one hundred thousand 
 parts, would be only -001 of au inch ; that is, if this depression 
 has been in existence one hundred thousand years, we must 
 believe that with all the dust there is in the air, and all the 
 soil that would wash down the steep incline of all the sides, 
 and all the vegetable matter growing in and falling into the 
 depression, one thousand years would be required for one inch 
 of sediment to accumulate ! If we reduce this supposed period 
 to 50,000, 25,000, and 13,500 years successively, the time re- 
 quired for the accumulation of an inch of sediment would be 
 proportionally 500, 250, and 125 years. If any one will be 
 at the trouble of dividing an inch into 125 equal parts, he will 
 probably be surprised at the insignificance of the quantity. 
 The' slowest rate at which Boucher de Perthes calculates for 
 the accumulation of peat over Roman pottery in the valley of 
 the Somrae is three centimetres, or a little over an inch, in a 
 century. 
 
 We do not bring railing accusation against those who, from 
 astronomical considerations, confidently speak of the close of 
 the Glacial period as an event which occurred scores of thou- 
 sands of years ago ; but it is important to know what other 
 
 * " Geology of New Hampshire," vol. iii, p. 327. 
 
THE DATE OF THE GLACIAL PERIOD. 575 
 
 beliefs that long chronology carries with it. If any one 
 chooses to believe that kettle-holes can stand one hundred 
 thousand years, and fill up only twentiJ^-four feet from the 
 apex of the inverted cone, he must run the risk of being 
 considered credulous. 
 
 In rejectingthe theory of Mr. CroU concerning an indefinite 
 succession of glacial periods, we did not mean to foreclose 
 the discussion connecting the question whether there have 
 not been several Pleistocene glacial epochs. This question 
 must, therefore, now be considered with more particular 
 reference to its bearing upon matters of chronology. As 
 the reader doubtless observed in the remarks upon Croll's 
 theory, quoted from Mr. Gilbert and President Chamber- 
 lin, in the preceding chapter, each of them spoke of an "In- 
 terglacial Period" as clearly indicated in North American 
 geology. The calculations just made relate to the chronology 
 of what President Chamberlin called the "second glacial 
 epoch." Niagara Falls, the Falls of St. Anthony, the kettle- 
 holes of Massachusetts, and the valley of Plum Creek, 
 are none of them upon the extreme border of the glaciated 
 region. Raccoon Creek is nearer the margin. Calculations 
 respecting those interior points, therefore, do not give the 
 date of the extreme marginal deposits. Hence it becomes 
 a matter of prime importance to consider to what extent 
 the ice retreated during the various climatic episodes 
 which characterized the epoch. Many, perhaps most, of 
 the authorities on glacial subjects at the present time hold 
 that during two or three of these episodes the ice retreated 
 as far as the Laurentian Highlands iand then re-advanced to 
 the limits of what are called respectively, the lowan, the 
 lUinoisan and the Wisconsin boundaries of glacial drift. 
 It is necessary, therefore, to discuss these questions in con- 
 siderable detail. 
 
 The most obvious evidence adduced in favor of inter- 
 glacial epochs in America consists of the so-called "inter- 
 
576 THE ICE AGE IN NORTH AMEBIGA. 
 
 glacial" forest-beds.* These forest-beds and vegetal de- 
 posits occur over a wide area, and in places have glacial de- 
 posits both under them and over them. The first supposi- 
 tion with regard to them was that these various forest-beds 
 were contemporaneous, and indicated a general retreat of 
 the ice after its first invasion of North America until it had 
 entirely disappeared or lingered only in the Canadian high- 
 lands ; whereupon there was a readvance of the ice, over- 
 whelming the forests and other vegetal deposits which had 
 collected in kettle-holes and other depressions, and burying 
 them beneath a second sheet of ground-moraine, where they 
 are opened to present inspection whenever wells penetrate 
 them or eroding streams expose them on their banks. But 
 it is not clear that these interglacial forest-beds might not 
 originate in front of the margin of the slowly retreating ice 
 if only there were comparatively brief periods of readvance 
 along successive lines of latitude. Thus they may belong to 
 various times of oscillation, both during the general advance 
 and dming the general retreat of the glacier. If, for ex- 
 ample, at any time during the period of advance there had 
 been a retrocession of the ice-front for a short distance, for- 
 ests and vegetable growth would soon have spread over the 
 marginal belt from which the ice had retreated, and, upon 
 a readvance, these would be overwhelmed and covered with 
 a new stratum of glacial deposition. In case of some of 
 the peat-beds, it is probably necessary to suppose that they 
 were formed where they are, and are really interglacial ; but, 
 in case of many of the fragments and logs of wood found 
 in the glacial deposit, we are not compelled to suppose an 
 interglacial origin. Wood wiU stand transportation in the 
 ground-moraine almost as well as bowlders, and it is by no 
 means certain that much of the timber found in the till may 
 
 * See Chamberlin, " Geology of Wisconsin," vol. i, chap, xv, especially 
 pp. 271-291 ; "Driftless Area," pp. 211-216; N. H. Winchell in "Proceedings 
 of the American Association for the Advancement of Science," vol. xxiv, 1876, 
 pp. B, 43-56 ; " Geology of Minnesota,'' vol. i of the " Final Report," pp. 363 
 el seq. ; J. S. Newberry, " Goological Survey of Ohio," vol. ii, pp. 30-33. 
 
Fig. 148.— Perpendicular eeotion of till at Oxford. Ohio, showing a piece of wood thiiH- 
 inches in diameter projecting from the face. This has evidently been transported in 
 the till like a bowlder. The section is about fifty feet ; portion shown, about fifteen 
 feet, near the middle. (United States Geological Survey ) (Wright.) 
 
578 THE JOE AGE IHT NORTH AMERICA. 
 
 not have belonged to the original forests which covered the 
 country in front of the first sheet of advancing ice. These 
 logs may have been picked up like the bowlders, and trans- 
 ferred to the south a long time after their original deposi- 
 tion. Thus, it may be that the " forest-beds " near the mar- 
 gin of the glaciated area are of m"ore recent origin than those 
 some distance back, since the ice in its final retreat may 
 have proceeded with few and slight oscillations. As Presi- 
 dent Chamberlin suggests, also, " certain subaqueous deposits 
 so closely resembled true till that they have been mistaken 
 for it, and there is perhaps no case of superposition of beds 
 supposed to represent two glacial periods that is not still 
 open to these doubts." * 
 
 President Chamberlin, whose knowledge of the facts 
 bearing on this subject is wider than that of any one else, 
 therefore does not rely so much upon the existence of in- 
 closed forest-beds and a supposed superposition of distinct 
 beds of glacial debris, in proof of distinct glacial epochs, as 
 upon certain other considerations of a more general nature, 
 such as the following : 
 
 The earlier drift is characterized, in the interior basin, 
 by a wide but relatively uniform distribution, manifesting 
 only occasional and feeble tendencies to aggregation in mo- 
 rainic ridges. It is not bordered, except in rare instances, by 
 a definite terminal moraine, but ends in an attenuated border. 
 It is not characterized by the prevalence of prominent drum- 
 lins or other similarly ridged aggregations. The phenomena of 
 glacial erosion connected with it are generally feeble. Glacial 
 striae are indeed present, even in the peripheral portions, but 
 the surface of the rock is not usually extensively planed. The 
 whole aspect of the deposit indicates an agency which spread 
 the drift over the surface smoothly, and relatively gently, with 
 little forceful action. The drainage phenomena are also of 
 the gentle order. "We have yet failed to find evidence of very 
 vigorous drainage connected with the older drift of the in- 
 
 * See " Geology of Wisconsin," toI. i, p. 272. 
 
THE DATE OF THE GLACIAL PERIOD. 579 
 
 terior basin except in osars and kames, whose conditions of 
 formation wete exceptional, but, on the contrary, abundant 
 proof of slow-moying waters and imperfect drainage, indicat- 
 ing low slope of the surface. 
 
 The later Glacial epoch, on the contrary, was character- 
 ized by strong glacial action, planing the rock-surface vigor- 
 ously, even up to the very limit of its advance. The glaciers 
 plowed up immense moraines about their edges, except on 
 smooth plains whose slope was away from the ice-movement. 
 The drainage was usually vigorous, and immense trains of glacial 
 gravel stretch away from the margin of the ice-sheet, reaching 
 great distances down the valleys and frequently filling them 
 to great depths with well-assorted material. The vigorous 
 action of the glaciers of the second epoch and the rapid drain- 
 age, in general, stand in marked contrast with the gentle 
 action and imperfect drainage of the earlier epoch. One of 
 the conditions that determined the distinction was probably 
 the difference in elevation that characterized the two epochs. 
 
 The interval between these two leading epochs we regard as 
 the chief interglacial epoch, representing a greater lapse of 
 time and a greater change in the dynamic agencies of the age 
 than the several other interglacial intervals, or episodes of 
 deglaciation, which mark the complicated history of the Ice age. 
 
 As belonging to the earlier Glacial epoch, we recognize two 
 drift-sheets that have been described by the geologists of the re- 
 spective States as occurring in southwestern Ohio, southern In- 
 diana, central and southern Illinois, eastern and southern Iowa, 
 northern Missouri, eastern Nebraska, and southeastern Min- 
 nesota. 
 
 Between these occur, at numerous points, vegetal and fer- 
 ruginous accumulations and other evidences of a non-glacial 
 interval. To this horizon belong the larger number of de- 
 posits described under the term "old forest-bed," but very 
 many vegetal deposits so referred do not, in our judgment, 
 belong there, but are referable to several distinct horizons.* 
 
 Others adduce as evidence of the distinct Glacial epochs 
 in North America the greater oxidization and general de- 
 
 * " Driftlesa Area," pp. 214, 215. 
 
580 THE ICE AGE IN NORTH AMERICA. 
 
 composition of the material upon the extreme border of the 
 glaciated region as compared with that of the kettle-moraine 
 in Wisconsin, and what is considered to be a moraine of corre- 
 sponding age in the regions both east and west. 
 
 A striking evidence of the reality of this difference in 
 oxidization is related by Professor Penck. When Mr. Frank 
 Leverett was visiting him in Germany the two went out 
 together into the Alpine fields where Professor Penck had 
 distinguished three well marked stages of glaciation of 
 increasing amounts of oxidization and erosion. These suc- 
 cessive periods of glacial and interglacial episodes he had 
 named after three streams in the foothills of the Alps in south- 
 ern Germany, where the deposits are tjTpically present; 
 viz., Mindel, Riss and Wiirm.* In every instanceMr. Leverett 
 was able to correlate these with the three divisions which he 
 had made in America; viz., the Kansan, corresponding to 
 the Mindel period; thelUinoisan to the Riss; and the Wiscon- 
 sin to the Wiirm. But he did not recognize the lowan. All 
 these identifications were made in the field without previous 
 knowledge of Professor Penck's determinations. But with 
 reference to this evidence it is to be noted: 
 
 1. That the more complete oxidization of the glacial 
 d&yris along the southern border and the greater decomposi- 
 tion of the granitic bowlders and pebbles distributed over this 
 border, are naturally accounted for by the obvious fact that 
 for the most part the material along the southern border, 
 and for some distance back from it, was that which was first 
 picked up by the advancing ice, and was probably already 
 oxidized and partially decomposed by the long-continued 
 action of preglacial agencies when the ice began its removal. 
 Its oxidization, therefore, may not be any true indication of 
 the remoteness of its transportation and deposition. It is 
 evident that every successive period of movement from the 
 north would operate upon lower strata of rock and upon the 
 masses which had been less affected by secular agencies of 
 
 * See above page 459. 
 
THE DATE OF THE GLACIAL PERIOD. 581 
 
 decomposition. Tiius it is natural that the more northern 
 moraines and glacial deposits, of various kinds, shouldiippear 
 fresher than the southern. 
 
 The peculiar facts brought to light concerning the oxidiza- 
 tion of the belt of oldest till, bordering the Wisconsin moraine, 
 in Pennsylvania, are worthy of close attention in this connec- 
 sion. As already noted. Professor Williams found by exten- 
 tive field work that the moraine as marked by Lewis and 
 Wright across Pennsylvania was not the extreme boundary of 
 glacial action, but lay on an average twenty or twenty-five 
 miles back from that boundary. This attenuated border was 
 referred to by Lewis and Wright as "the fringe," but they 
 did not endeavor to ascertain its limit in that state. The 
 deposits over that area would, however, now be correlated 
 without doubt with those of Kansan age in the Mississippi 
 Valley. 
 
 It is noteworthy, therefore, that the surface outcrops 
 over this attenuated belt (examined in thousands of places and 
 at all elevationsineastern Pennsylvania up to 650 feet above 
 tide, and under caps of glacial deposits only a few feet thick, 
 that vary from loose gravels to compact clays) are universally 
 fresh and undecomposed, showing that the already oxidized 
 deposit was laid upon a freshly glaciated surface, and that 
 time enough has not since elapsed to decompose or oxidize 
 the gneiss, limestone, and slate rocks to any appreciable 
 extent. A striking illustration of this has already been given 
 in connection with the mammoth coal-beds at Morea, Pa., 
 within one mile of the extreme limit of glaciation, and twenty- 
 five miles south of the moraine of Lewis and Wright (p. 154). 
 Here the surface of the rock is distinctly glaciated, and 
 covered with from six to ten feet of sandy till through which 
 water easily percolates. But the coal is rotted only to the 
 depth of three-fifths of one inch, while immediately south of 
 it, in the unglaciated region, it is rotted to the depth of many 
 feet. 
 
582 THE ICE AGE IN NORTH AMERICA. 
 
 2. The till over this attenuated border is a mixture of 
 fresh and oxidized material at all levels, showing that most 
 of the oxidization preceded the glaciation, and that not suffi- 
 cient time has elapsed since for the oxidization of the fresh 
 material picked up by the glacier. This statement is based 
 upon the examination of sections miles in length; when it 
 everywhere appears that there is such a mixture of fresh 
 material with oxidized material that the conclusion is irre- 
 sistible that it was one movement which brought both. 
 
 For example, in the vicinity of Warren and south of Oil . 
 City at an elevation of 380 feet above the Allegheny River 
 numerous pebbles were found, both of sedimentary and of 
 granitic rocks, which had evidently been oxidized nearly to 
 their center before starting on their journey from Canada, 
 but had been planed down on one side so as almost to expose 
 the core on that side, while leaving the oxidized layers undis- 
 turbed on the other. Som e of these described were five inches 
 or more in diameter and had been rotted so that only an 
 inch or more of fresh nucleus remained; while in some cases 
 the unoxidized core was exposed through the glacial erosion 
 of one side. These instances were numerous. Mr. Williams 
 informs me that " one striking peculiarity in those with joint 
 planes through which the water could readily reach the 
 center, was that the relative permeability of the mass from 
 its different sides did not have the slightest influence on the 
 position of the fresh nucleus. It was as often nearer the side 
 whence water could most easily enter than to any other side. 
 This impressed me greatly," he says, "asan indication of the 
 extrem.e recency of the final shaping as with time the relative 
 porosity of the various sides would tend to bring the re- 
 maining nucleus under the usual law as to position." 
 
 I am permitted, also, to use the following extract from 
 Professor William's unpublished notes, in which he sums up 
 some most significant facts concerning the Kansan advance : 
 
 "The glaciated outcrops in the east [in Pennsylvania] are 
 
THE DATE OF THE GLACIAL PERIOD. 583 
 
 solid: those in the west more oxidized and rotten, but the 
 critical condition in the west as in eastern Pennsylvania 
 is the constant presence and mixture of fresh rolled material. 
 As the age of the mixture is the age of the freshest part, 
 there is finally no difference between the ages of the eastern 
 and western Kansan drift. 
 
 The rustiness of thewestern gravels shows that they were 
 the rolled and weathered surface fragments picked up by 
 the ice, and modified by its action. With the crystallines 
 which are thoroughly oxidized to their center, we find a 
 few specimens which look on one side like a piece of rusty 
 gravel. The black bisilicates have entirely disappeared, 
 and have left pits and a rusty staining. The feldspar also 
 has kaolinized. In these very old ones, the glaciated sides 
 were never scraped down to the fresh interior, but uniformly 
 show a rusty though solid exterior, quite smooth and firm 
 to the hammer. 
 
 "By breaking these, we would find that the solid nucleus 
 might be one-eighth of an inch from one side which had been 
 glaciated, and three inches or more from the other side which 
 had remained unglaciated." 
 
 I am not aware that adequate attention has been paid to 
 this class of facts over the Illinoisan and Kansan areas in the 
 Mississippi Valley, but I was much impressed with the fresh- 
 ness of the Canadian bowlders which were found at Tus- 
 cumbia, on the Osage River, in central Missouri, and by the 
 freshness of many of the pebbles in a great gravel-pit at Hol- 
 liday on the Kansas River a few miles above Kansas City to 
 which the railroads have resorted for a long time for ballast 
 and which contains much material from the far north. 
 
 In this connection it is proper to call special attention to 
 the accumulating evidence going to show that the glacial 
 movement from the Keewatin center was not strictly con- 
 temporaneous with that from the Labradorian center but 
 preceded it by a longer or shorter interval. 
 
 In the first edition it was suggested that the remarkable 
 re-entrant angle in the glacial border at Salamanca, N. Y., 
 indicated the junction of two ice-movements from widely 
 
584 THE ICE AGE IN NORTH AMERICA. 
 
 separated centers of accumulation to the northeast and north- 
 west. Positive evidence in support of this was found, as 
 already stated, by Prof. Williams in 1897 in the discovery of 
 a rolled piece of native copper from Lake Superior firmly 
 imbedded in till at East Warren, Pa., forty feet below the 
 surface, showing that the older ice-movement from the north- 
 west invaded the region now coverd with the later deposits 
 from the northeast to the extent of several hundred miles; 
 for, as already shown, northeastern drift extended some dis- 
 tance across the Mississippi at Burlington, Iowa. 
 
 The most important evidence supposed to indicate the 
 complete retirement of the continental ice-sheet between 
 successive deposits is found near Toronto, Canada. This was 
 first investigated by Dr. G. J. Hinde in 1878, but has since 
 been more thoroughly studied by Professor A. P. Coleman, of 
 Toronto University. Briefly stated the facts are that in the 
 valley of the Don River and at Scarboro Heights near Toronto 
 there is at the base a deposit of till which after having been 
 extensively eroded was covered by sedimentary deposits 150 
 feet in thickness which had been brought into standing water 
 by the stream to form a delta whose base extended twenty-five 
 or thirty miles along the shore. The lower strata of this delta 
 deposit are thirty-five feet below the present level of the lake, 
 and probably at about the same relative level as when laid 
 down. But the water from some unknown cause rose as the 
 accumulation progressed until it was 150 feet higher than 
 now, when the upper sediments of coarser gravel were depos- 
 ited the water began to fall, and a period of erosion succeeded. 
 
 This proceeded until at Scarboro a V-shaped channel, 
 one mile wide at the top and 150 feet deep, was worn in the 
 sedimentary deposits, whereupon the ice advanced again 
 and covered the whole with sheets of bowlder clay and 
 assorted drift to a total depth of 200 feet. Here certainly 
 seems to be an interglacial deposit of unusual extent. 
 
 Nor is the character of the fossil plants and animals 
 included in the interglacial deposits any less noteworthy. 
 
THE DATE OF THE GLACIAL PERIOD. 585 
 
 Both the fauna and the flora of the lower, or Don, beds indi- 
 cate a much warmer climate than those of the upper, or Scar- 
 boro beds. In the Don beds there are found leaves and wood 
 of maple, elm, ash, hickory, basswood, and even of pawpaw 
 and osage orange which now flourish only in latitudes several 
 degrees south of Toronto. Also, of the mollusks found in the 
 Don beds, four of the species are not now found in the St. 
 Lawrence basin, but only after passing the watershed which 
 separates it from that of the Mississippi. 
 
 On the other hand, the upper, or Scarboro sands and 
 clays are wanting in the species indicating a warmer climate 
 but abound in both a flora and a fauna suggestive of Labra- 
 dor and of the region north of Lake Superior. 
 
 In the opinion of Professor Coleman these facts cannot 
 be accounted for except on the supposition that the earlier 
 ice-sheet retired from practically the whole region to the 
 northward before the latter one began its advance; which 
 certainly looks very reasonable at first sight. But there are 
 a number of considerations, too much overlooked, which 
 perhaps permit a contrary conclusion. 
 
 1. We are not warranted in assuming that the advance of 
 the ice was simultaneous from the Keewatin and the Labra- 
 dorian centres. On the contrary it seems certain, as has been 
 shown above, that the advance from the Keewatin center 
 was much earlier than from the other. The so-called Kansan 
 till underlies the Illinoisan for several hundred miles east of 
 the Illinoisan border. For example the Illinoisan ice crossed 
 the Mississippi at Burlington, Iowa, and advanced many 
 miles westward. But Kansan ice had at an earlier time 
 spread eastward so as to carry Lake Superior copper as far 
 as Warren in Western Pennsylvania. In a previous chapter 
 (p. 527) attention is called to the fact that the boundary of 
 the glaciated areas in the central and eastern parts of the 
 United States consists of the arcs of two circles with their ■ 
 centers respectively in Labrador and the Lake Superior region. : 
 This will appear at a glance by consulting the map. Now, 
 
586 THE ICE AGE IN NORTH AMERICA. 
 
 the junction of these arcs is at Salamanca, New York, almost 
 exactly on the meridian of Toronto. It is therefore a plau- 
 sible hypothesis that the lower till at Toronto was deposited 
 by the Keewatin ice-sheet near its eastern margin and that 
 it withdrew some time before the Labradorian sheet reached 
 that point. 
 
 This opens up a wide field of speculation connected with 
 our theories of the cause of the spread of the various ice-sheets. 
 On the theory that elevation of land is the prime cause it 
 would appear that the rise of land proceeded in a wave from 
 west to east. The Keewatin center therefore rose first and 
 sent out its ice-sheets far south toKansas,and east to Pennsyl- 
 vania. Then as it began to sink under its accumulating load 
 of ice, the eastern or Labradorian center began to rise and in 
 due time started its glaciers to meet the vanishing ones from 
 the Keewatin center. But, possibly long before Toronto was 
 reached by the Labradorianice-sheet, the Keewatin glacier had 
 retired from its eastern limit amid conditions of climate that 
 were essentially preglacial. For it must be borne in mind that 
 the retreat of the ice can only take place when the climate is 
 abnormally warm. Indeed such warmth would seem to be 
 essential for the melting of the ice. 
 
 An interesting direct.proof of this was found by Dr. Hoist 
 in southern Sweden, where he excavated gravel beds in front 
 of the principal moraine which contained remains of plants 
 and animals characteristic both of warm and cold climates 
 in close connection, and which must have been contemporane- 
 ous. Similar facts were reported to me by Professor Tscher- 
 naschev from Finland. It is also well known that large species 
 of oysters lived long after the glacial epoch in Maine, especially 
 at Damariscotta, which do not survive except on our southern 
 coasts. It is in point also to instance the spread of the masto- 
 don, the mammoth, the rhinoceros and even the hippopot- 
 amus under the conditions which prevailed in northern 
 Europe and Asia during the glacial period. 
 
THE DATE OF THE GLACIAL PERIOD. 687 
 
 A further line of inferences follows from studying the 
 probable cause of the rise of the water in Lake Ontario dur- 
 ing the accumulation of the interglacial delta at Scarboro. 
 This, as we have stated, w as 150 feet, and the deposits at the 
 bottom indicate a warm climate, and those at the top a cold 
 climate. Now if v(e study the conditions involved it will 
 appear that there is strong confirmation of the theory just 
 advanced. Evidently, as Professor Coleman points out, 
 the deposition of the Don beds began when the level of Lake 
 Ontario was just about what it is at the present time. That 
 would imply that its outlet was still through the St. Lawrence, 
 which must then have been unobstructed by ice. But as the 
 Labradorian ice advanced and closed up this outlet the water 
 level would eventually rise to the height of the col at Rome, 
 N. Y., leading through the Mohawk into the Hudson River. 
 This is 200 feet above Lake Ontario. But as it is shown that 
 now the axis of post-glacial elevation is the Mohawk Valley, 
 the north shore of Lake Ontario may well have been rela- 
 tively fifty feet higher during glacial times than it is now, 
 which would bring the elevation of the col at Rome into exact 
 harmony with that of the upper Scarboro beds. Under this 
 theory we have that gradual passage from warm to colder 
 conditions which we need to account for the change in species 
 in passing from the lower to the upper beds. And this is 
 just what Dr. Lamplugh has shown to be the case in the 
 glacial deposits of England.* 
 
 2. The uniformity in the distribution of the till over the 
 southern portion of the glaciated area in the Mississippi 
 Valley is partly an illusion, due to the fact that the great 
 amount of loess covering the region, especially in southern 
 Indiana and Illinois and in eastern Nebraska, prevents, to a 
 considerable extent, observations upon the original surface, 
 and this loess, as has already been shown, is doubtless the 
 
 * "Presidential Address to the Geological Section of the British. 
 Association for the Advancement of Science," at York, 1906. 
 
588 THE ICE AGE IN NORTH AMERICA. 
 
 finer part of the glacial dibris carried southward by the gla- 
 cial streams — so that, upon any theory, we should expect a. 
 much larger accumulation of loess over the southern portion 
 of the area. 
 
 Mr. Leverett relies largely on thegreat erosion of the Kansas 
 sheet till as an indication of its age. He estimates, for example, 
 that in northern Missouri not over thirty per cent of the origi- 
 nal plain is left upon the retreat of the ice, in the narrow tabu- 
 lar remnant remaining upon the divides. "The streams are 
 flowing in valleys that have broad slopes and bottoms, the 
 slopes being so toned down as to fall generally below 6° and 
 not imcommonly to 3° or even less. The slopes of the valley, 
 twenty-five meters in depth, often have a breadth of about a 
 kilometer, and the bottoms of small drainage lines often 
 exceed a kilometer in width. Topographic sheets of the 
 United States Survey, which well illustrate the post-Kansan 
 erosion, are the Atlanta, Edina, and Kahoka quadrangles of 
 northern Missouri." (See comparison of North American 
 Glacial Deposits, from "Zeitschriftfur Gletscherkunde," vol. 
 iv, p. 258). 
 
 With this he compares a part of the Belleville, III., topo- 
 graphic sheet which shows 60 per cent or more of the original 
 glacial plain untouched by erosion; but again in the lowan 
 drift (which Mr. Leverett would now identify with the Illi- 
 noisan epoch), the portion of the glacial plain which is undis- 
 sected is not greatly in excess of the Kansan plain from 
 Missouri. 
 
 It should benoted furthermore that the blanketof Kansan 
 till is comparatively imiform over its whole area. There are 
 no moraines in it, and there never were any. Moreover, the 
 deposit was rarely thick enough to disguise the preglacial 
 topography. Much of the supposed evidence of post-glacial 
 erosion is probably the result of this failure of the glacial 
 deposits to fill the valleys and channels of the original topog- 
 raphy.- 
 
Fig. 149— Part of Altanta, Missouri topographic sheet. Scale A Million or 1:83333. 
 ContourlntervalZOfeet. Illustrates post-Kanaan erosion. 
 
 FlQ.150— PartofOelweln, lowa.topographlcsheet. Scale! orl.666660. Conluurlaterval 
 20 feet. Ill ustratos erosln In the so-called lowan drift. 
 
590 THE ICE AGE IN NORTH AMERICA. 
 
 The controlling influence of the preglacial topography may 
 be observed in the neighborhood of Galesburg, Illinois, where 
 all along the divide between the Illinois and Mississippi 
 rivers the surface presents an extensive general level, covered 
 with glacial drift of Illinoisan age to a considerable depth. 
 But as one proceeds on either side towards the rivers men- 
 tioned the size of the preglacial valleys increases so rapidly 
 that the glacial blanket is not sufficient to disguise them, 
 while near the water-shed on both sides appear the original 
 extensive amphitheaters characteristic of valleys of extreme 
 age. 
 
 Evidently the post-glacial erosion is not by any means so 
 great as would at first appear to be the case. But what seem 
 to be valleys of post-glacial erosion are simply adjustments of 
 the glacial blanket to the precedent valleys of erosion. 
 
 Again, the broad valleys bordering the south-flowing 
 streams of gentle gradient in the Illinoisan and Kansan 
 regions differ only in moderate degree from similar valleys 
 in the Wisconsin area. As instances I would note the valleys 
 of the Nishnabotna, the Tarkio, the Nodaway, and the 
 Platte rivers of northwestern Missouri, all of which rise in 
 southwestern Iowa, and, after flowing long distances, enter 
 Missouri. One can but be impressed in crossingthesevalleys 
 with their great width, and with the signs that they were 
 occupied by immensely larger streams of water than it is 
 possible to provide under present conditions. On comparing 
 these valleys with that of the river Styx, a small stream in 
 Wisconsin drift just south of the water-shed inMedinaCounty, 
 Ohio, we find a very small stream occupying a level flat- 
 bottomed valley, a third of a mile wide, which is evidently 
 the product of the lingering ice and the floods pouring through 
 the valley during the melting of the late Wisconsin period. 
 The contrast between this valley and the valleys in north- 
 western Missouri is by no means great, certainly not so great 
 as to imply an enormous lapse of time between their formation. 
 
THE DATE OF THE GLACIAL PERIOD. 591 
 
 In both cases, doubtless, the wide troughs were preserved 
 by the presence of lingering masses of the melting ice sheet. 
 
 3. The theory of a general depression of the glaciated 
 area with reference to the sea-level may apply to a certain 
 portion of a single period as well as to one of two distinct 
 periods. We may suppose a low slope of a surface and the 
 consequent imperfect drainage and slow-moving waters dur- 
 ing the maximum extent of a single glacial epoch as well 
 as during the first of two epochs. The theory that tlie 
 weight and attraction of the ice were tangible factors in pro- 
 ducing the relative depression of land which characterized a 
 portion of the Ice age would lead us to expect the greatest 
 depression during the period of maximum extension. When 
 the ice-front had retreated from Carbondale, 111., to Mad- 
 ison, Wis., the intervening area had been reheved from an 
 enormous amount of pressure. 
 
 4. With reference to the comparative absence of glacial 
 striae and of planing and grooving over the southern area, it 
 should be noted, first, that fresh exposures of rock in that 
 region are very infrequent, owing to the great depth of till 
 and loess ; and, secondly, that upon any theory the gla- 
 cial grooving and striation would necessarily grow fainter as 
 the boundary was approached, because the movement of ice 
 over that portion was so much less than over the central and 
 northern portions; and, thirdly, the absence of planation 
 is not relatively so great as is sometimes represented. The 
 grooves and strise in Highland and Butler counties, Ohio, 
 very near the margin, and in southwestern Indiana and 
 southern Illinois, still nearer the margin, are as clear and 
 distinct as can anywhere be found. Also, upon the surface 
 of the limestone rocks, within the limits of the city of St. 
 Louis, where the glacial covering was thin, and disintegrat- 
 ing agencies had had special opportunities to work, I found 
 very clear evidences of a powerful ice-movement; and at 
 Du Quoin, 111., only forty or fifty miles back from the ex- 
 treme limit of glaciation, I was greatly impressed with the 
 extent to which the surface rock had been planed, by ex- 
 
592 THE ICE AGE IN NORTH AMERICA. 
 
 amining the fragments brouglit up from a shaft which had 
 recently been sunk first through fifty or sixty feet of surface 
 soil, and then for some distance into the rock. The small 
 fragments from the surface of the rock thrown up were 
 most beautifully planed and striated. 
 
 A thorough study of the condition and distribution of 
 the buried forest-beds bears strongly, as I can not but think, 
 against the complete separation of glacial epochs in North 
 America. In addition to the facts about to be enumerated, 
 it is a significant circumstance that the buried vegetable de- 
 posits under consideration do not mark a warm climate, but 
 a climate much colder than the present — such a vegetation, 
 in fact, as would naturally flourish near the ice-margin. The 
 buried forests of southern Ohio have a striking resemblance 
 to those we described in Glacier Bay, Alaska. Peat and 
 hardy coniferous trees are predominant. 
 
 One of the most instructive localities in which to study 
 organic remains embodied in glacial deposits is in the region 
 included in the southern part of Montgomery and the north- 
 ern part of Butler county, Ohio. The glacial deposits con- 
 taining organic remains in that vicinity were first described 
 by Professor Orton, of the Ohio Survey, in 1870.* Near 
 Germantown, on Twin Creek, in Montgomery county, about 
 thirty miles north of Cincinnati, there is exposed, at a sharp 
 angle of the stream, a perpendicular bank of drift ninety-five 
 feet in height. Underneath this is a deposit of peat as much 
 as fourteen feet thick. The upper portion of the peat " con- 
 tains much undecomposed sphagnous mosses, grasses, and 
 sedges." Both the stratum of peat and the clayey till above 
 "contain many fragments of coniferous wood, some of 
 which can be identified as red cedar {Jxmipents Yirginia- 
 nuii).^' Immediately above the peat-bed there is from fifteen 
 to twenty-five feet of what seems to be true till. This shows 
 no sign of stratification, and abounds in striated stones. 
 Next above occurs a band about ten feet thick of stratified 
 
 * " American Journal of Science," toI. c, 1870. 
 
THE DATE OF TEE GLACIAL PERIOD. 593 
 
 material containing coarse gravel and a good deal of tine 
 sand. Above this to the top seems again to be true till, 
 
 Fig. 151.— Section of till near Genmmtowii, Ohio, ovi-rlying ttiick bt-d of peat. The man 
 in the picture stands upon a shelf of peat from which the till has l)eeM eroded by Hie 
 stream. The dark spot at the right hand of the picture, just above the water, is an 
 exposure of the peat. The thickness of the till is ninety-flve feet. The partial strat- 
 ification spoken of in the text can be seen about the middle of the picture. The fur- 
 rows up and down had been made by recent rains. (United States Oeological Sur- 
 vey.) (Wright.) 
 
 with, however, an occasional pocket of sand or thin stratum 
 of stratified material. But, both up and down the stream 
 from this point the till merges into gravel-beds ])artia]ly ce- 
 
594 THE ICE AGE IN NORTH AMEBIGA. 
 
 mented together by infiltrations of Kme and iron. Down 
 the stream the stratum of peat rises to a higher level, so as 
 eventually to come in contact with the first band of stratified 
 material just mentioned, the intervening till gradually thin- 
 ning oat between them. The appearance is that of a saucer- 
 shaped deposit of peat such as would have formed in a ket- 
 tle-hole, and which was subsequently filled and covered with 
 the advance of the glacier. 
 
 That the facts indicate a somewhat prolonged interval 
 between the first advance of the ice over the immediate re- 
 gion and the second, can not, therefore, well be denied, for 
 the peat is clearly enough between two glacial deposits. But 
 it may well be questioned whether an interval of two or three 
 centuries would not suffice for the accumulation of the peat 
 described ; for it will be observed that it seems to have oc- 
 curred in a large kettle-hole in which the vegetable matter 
 naturally gravitated toward the center and is much deeper 
 there than near the edges. It is not therefore allowable 
 to take the extreme thickness of peat as the measure of the 
 amount of accumulation during the interglacial period. 
 
 As to the rapidity with which peat may accumulate in 
 favorable circumstances, we can do no better than transfer 
 a recent discussion of the subject from the pen of the veteran 
 botanist, Leo Lesquereux, contributed to the " Annual Report 
 of the Pennsylvania Geological Survey for 1885 " : * 
 
 Two conditions are necessary for the origin and gi'owth 
 of peat — water either stagnant in basins, lakes, pools, etc., or 
 water abundantly supplied by a boggy atmosphere, increased 
 by dense forest-growth. 
 
 Pools of stagnant water, when not exposed to periodical 
 drying up, are invaded by a peculiar vegetation : first, mostly 
 composed of confervm, simple, thread-like plants, of various 
 color and of prodigious activity of growth, mixed with a mass 
 of infusoria, animalcules, and microscopic plants, which, partly 
 decomposed, partly continuing the floating vegetation, soon 
 
 Pages 106, 107, 113, 114. 
 
THE DATE OF THE GLACIAL PERIOD. 595 
 
 :fiU the basins, and cover the bottom with a floating of clay- 
 like mold. So rapid is the work of these minute beings, that 
 in some cases from six to ten inches of this mud is deposited 
 in one year. Some artificial basins in the^large ornamental 
 parks of Europe have to be cleaned of such muddy deposits of 
 rfloating planbs, mixed with small shells, every three or four 
 years. 
 
 When left undisturbed this mud becomes gradually thick 
 and solid — in some cases of great thickness, affording a kind 
 of soil for the growth of marsh-plants, which root at the bot- 
 tom of the basins or swamps and send up their stems and 
 leaves to the surface of the water or above it, where their 
 substance becomes in the sunshine hard and woody. 
 
 As these plants periodically decay, their remains, of course, 
 drop to the bottom of the water ; and each year the process is 
 repeated, with a more or less marked variation in the species of 
 the plants. After a time the basins become filled by these suc- 
 cessive accumulations of years or even centuries, and then the 
 top surface of the decayed matter, being exposed to atmos- 
 pheric action, is transformed into humus and is gradually cov- 
 ered by other kinds of plants, making meadows and forests. 
 
 In this way many deposits of peat are buried under- 
 ground and remain unknown until discovered by diggings or 
 borings. Such are the immense peat deposits in the great 
 swamps of Virginia, the Dismal Swamps, and all along the 
 shores of the Atlantic from Norfolk to New Orleans. 
 
 In other cases when basins of stagnant water are too 
 deep for the vegetation of aquatic plants, Nature attains the 
 same result by a different special process, namely, by the pro- 
 longed vegetation of certain ki^ids of floating mosses, espe- 
 cially the species known as sphagna. These floating masses 
 grow with prodigious speed, and, expanding their branches in 
 every direction over the surface of ponds or small lakes, soon 
 cover it entirely. They thus form a thin floating carpet, which, 
 as it gradually increases in thickness, serves as a solid soil 
 for another kind of vegetation, that of the rushes, the sedges, 
 and some kinds of grasses, which grow abundantly mixed with 
 the mosses, which by their water-absorbing structure furnish a 
 persistent humidity sufficient for the preservation of their re- 
 
596 THE JOE AGE IN J^ORTH AMERiGA. 
 
 mains against aerial decay. The floating carpet of moss be- 
 comes still more solid, and is then overspread by many species 
 of larger swamp-plants and small arborescent shrubs, espe- 
 cially those of the heath family ; and so, in the lapse of years 
 by the continual vegetation of the mosses, which is never inter- 
 rupted, and by the yearly deposits of plant remains, the carpet 
 at last becomes strong enough to support trees, and is changed 
 into a, floating forest, until, becoming too heavy, it either breaks 
 and sinks suddenly to the bottom of the basin, or is slowly 
 and gradually lowered into it and covered with water. . . . 
 
 The absorbing power of the peat-mosses enables them to 
 grow higher and higher above their original water-level, from 
 which they thus gradually emerge. The name emerged bogs 
 has been therefore given them. 
 
 The peat of emerged bogs is less compact ; the annual 
 layers are more distinct, generally well defined in their succes- 
 sion. At the top of the bog the layers measure about one inch 
 in thickness, at the bottom less than one eighth inch, and 
 in old bogs still less. The growth, therefore, though not very 
 rapid, is easily observed and registered in several ways. 
 
 It may be measured by compass and level from the border 
 of the swamp, the central portion of which becomes gradually 
 higher and higher, screening from the view of a spectator on 
 one side of it objects which had been before observable on the 
 other side of it. 
 
 It may be estimated also by a time-scale, in cases where 
 ancient bridges, pavements, etc., whose epoch of construction 
 is certified by documents, are discovered buried under beds of 
 peat of known thickness. 
 
 Again, in places where peat-bogs have been worked for a 
 number of years, old pits are encountered, now entirely re- 
 filled ; and when this happens with peat, during the life of 
 the proprietor, who has himself dug the old pits and can recall 
 the exact date, very precise data are thus furnished for learning 
 the amount of time necessary for the reproduction of a given 
 thickness of peat. 
 
 The rate of growth depends, of course, on atmospheric or 
 other local circumstances, but, putting together many such 
 pieces of documentary testimony obtained in different eoun- 
 
THE DATE OF THE GLACIAL PERIOD: 597 
 
 tries, the average production of compact matter may in a 
 general way be estimated at one foot in a century. 
 
 In immerged logs, formed of vegetable debris falling into 
 water, the peat grows more slowly and less regularly. The 
 actual rate of its growth has not yet been positively recorded. 
 In very extensive bogs, stretching between Swiss lakes, timber 
 posts have been discovered on the line of an old road, and 
 parts of a bridge buried beneath five or six feet of compact, 
 black peat. Although the exact date of these constructions 
 has not been fixed, the discovery of Eoman medals in the 
 vicinity suggests the beginning of the Christian era. This 
 shows that the kind of peat which results from the maceration 
 of plants under water is of much slower growth than the peat 
 layers of the emerged hogs. It is also more compact, and ia 
 quite black, the vegetable matter being more completely de- 
 composed, and its internal structure generally so destroyed as 
 to be unrecognizable. The peat of emerged hogs, on the con- 
 trary, is yellowish-brown, fibrous, its annual layers distinct, 
 and the woody fragments more generally recognizable. 
 
 Since the above was written a well sunk at Germantown 
 through the till 100 feet deep, nearly a mile northeast of the 
 exposure shown on p. 593, penetrated a peat layer several 
 feet in thickness, showing that the deposit is extensive and 
 perhaps older than we had estimated. It should also be said 
 that Mr. Leverett is not fully convinced thatthe gravel under- 
 neath the peat is glacial, but thinks that it probably is. 
 
 But we are not compelled to assume a slow growth, nor 
 even the average grovrth as the rate. The cool, moist climate of 
 a glacial age would seem to be peculiarly favorable to both 
 the growth and the preservation of peat ; so that two hun- 
 dred or three hundred years is perhaps ample for the pro- 
 duction of all the facts connected with the peat accumula- 
 tions at this point. If it be asked how such a deposit of 
 peat could be overwhelmed with ice without disturbance, the 
 answer is that, as suggested by N. H. Winchell, before ohe 
 reinvasion of ice the peat in the kettle-hole and probably tie 
 
598 THE ICE A GB IN NORTH AMERICA. 
 
 rim of the whole had become frozen, and so capable of re 
 taining its form. 
 
 Similar deposits of peat in superficial kettle-holes are very 
 frequent in the glaciated region, and constitute an important 
 portion of the reserved stores of fuel laid up for tlie future 
 use of man. Professor Lewis and myself had an excellent 
 opportunity to study such a modem deposit at Freehold, 
 Warren county. Pa.* Here one half of such a hole had 
 
 Fig. 152.— Section of kettle-hole in Freehold, Pennsylvania. (See text.) 
 
 been removed in making a road, and exposed a complete 
 and fresh section through the middle. The depth of the 
 peat in the middle was six feet, growing gradually thin- 
 ner in each direction toward the sides. Peat and soil were 
 mingled in alternate layers near the edges. ITumerous logs 
 of prostrate trees were also imbedded in the peat. It is 
 evident that had there been a readvance of the ice over this 
 region after the above accumulation was complete, and had 
 the soil become frozen, there would have been at Freehold 
 an interglacial deposit of vegetable matter closely analogous 
 to that described at Germantown. 
 
 A comparatively short interval between the periods of 
 recession and advance of the ice-front in southern Ohio is 
 also indicated in numerous places where fragments of wood 
 are found imbedded in true glacial deposits near the glacial 
 margin. For example, near Darrtown, on Four- Mile Creek, 
 in Butler county, Ohio, is an exposure of till, sixty-five feet 
 high, containing fresh red-cedar logs near the bottom, and 
 fragments of wood in all conceivable positions throughout 
 the lower half of the deposit. The deposit is true till, being 
 unstratified and full of scratched stones, many of which are 
 granitic. There is, however a line of stratified material 
 
 ■ Spc " Second Geological Survey of Pennsylvania, Z," p. 171. 
 
TEE DATE OF TEE GLACIAL PERIOD. 
 
 599 
 
 about half-way up the bank, which is about two feet thick, 
 and contains pebbles several inches in diameter. Not much 
 
 Km. l.a. -Srctioli ill lill IICIII- l),lirliiwil, Blllirr Coilllly. Dllin, .si\ty-li\r I\tI liii;ll. 
 
 Coarse line of t^tratification near the middle. Fresh cedar logs at the bottom. (See 
 text.) (United States Geological Survey.) (Wright.) 
 
 wood is found above this line, vet there is 8on:e, and the 
 structure above seems identical with that below. All this 
 would .^eera to indicate that there was a temporary retreat of 
 
600 THE lOE AGE IN NORTE AMERICA. 
 
 the ice, when for a short time water sorted and deposited 
 material over the lower stratum of till ; then there was a re- 
 advance, pushing along a vast mass of unsorted material over 
 the stratified stratum without disturbing it. In the deposit 
 already described near Germantown, evidence of as many as 
 four such marks of successive advances and retreats can be 
 seen. 
 
 Again, near Oxford, in Butler county, a few miles up 
 the same stream (Four-Mile Creek) from Darrtown is an ex- 
 posure of till where the unstratified character is perfectly 
 manifest in which I observed and photographed a piece of 
 wood, well preserved, projecting from the perpendicular face 
 of the bank about forty feet below the surface, and where no 
 land-slide could have occurred.* Equally good sections were 
 also seen on Aunt Ann's Kun, near the city of Hamilton, in 
 the same county, and only about twenty miles north of Cin- 
 cinnati. 
 
 Usually, as has been remarked, these buried deposits of 
 peat and wood have been assumed to imply the existence of 
 two distinct glacial periods. But, from what has been said 
 above, it would appear that the facts point rather to shorter 
 periods of advance and recession of the ice-front, analogous 
 to those which are now in progress m the Alpine glaciers, as 
 heretofore noted. That/the interval between the two move- 
 ments noted at Darrtown was comparatively short is evident 
 from the fact that the fragments of wood found mingled 
 with the till, both above the stratum of stratified material 
 and below it, are identical in kind, and are in a similar state 
 of preservation. This locality is about twenty miles back 
 from the glacial margin. 
 
 In the instances next mentioned of wood being found 
 imbedded in glacial deposits the locality is still nearer the 
 glacial margin, and, instead of being interglacial are pre- 
 glacial — that is, the vegetable remains have glacial deposits 
 over them but not under them. 
 
 * See Fig. 14S, p. 577. 
 
THE DATE OF TEE GLACIAL PERIOD. 601 
 
 A sycamore log was reported to me as found at Morgan- 
 town, Morgan county, Ind., thirty feet below the surface. 
 This is, however, in a stratified deposit, but one which was 
 evidently formed in connection with the last stages of the 
 Glacial period at tha;t point. It is one quarter of a mile back 
 from the little creek running through the village, and the 
 glacial limit is but a few miles south, on the higher lands of 
 Brown coimty. 
 
 Again, near Seymour, Jackson county, Ind., logs of wood 
 are reported as occasionally found in digging wells in the 
 village at a depth of twenty feet below the surface. Sey- 
 mour is on a glacial terrace, in the line of one of the largest 
 glacial floods carrying off the melting torrents from the de- 
 caying ice over a good part of southeastern Indiana. The wide 
 terrace on which Seymour stands, and in which -the logs are 
 found, is about sixty feet above the present bed of the East 
 Fork of White Eiver, running through the place. Black- 
 walnut logs are also mined from the banks of the river in 
 low water. This instance is not probably decisive of the 
 age of the buried wood, as the terrace may be the product 
 of the so-called second Glacial period. Still, there can 
 be no doubt that the most recent glacial advance extended 
 to the borders of Brown county, which lies a little west of 
 the locality just spoken of, and which is nearly in the lat- 
 itade of Butler county, Ohio, alluded to in a previous para- 
 graph. 
 
 Another most decisive instance of vegetable remains in 
 till near the margin occurs in Bigger township, in the south- 
 eastern comer of Jennings county, Ind. Here Mr. Burchill 
 reported to me the finding of wood m a well, twelve feet 
 deep, in a hard blue clay wMch, from neighboring exposures, 
 is, without doubt, true till. On another farm, near by, wood 
 was reported to me as found thirty feet below the surface in 
 a well that failed to reach the rock at that depth. This ia 
 on aa high land as there is in that region, and is about ten 
 miles north of Madison, on the Ohio Eiver, and about five 
 hundred feet above it. 
 
602 THE ICE AGE IX NORTH AMERICA. 
 
 Professor Borden * reports a well at Paris Crossing, in 
 Jefferson county, about twelve miles southwest of the fore- 
 going place, in blue-drift clay forty feet below the surface. 
 The same authority also reports a well at Milan, near the 
 summit of Kipley county, Ind., which is as far south as Cin- 
 cinnati, and about twelve miles northeast from the river, with 
 muck and wood fifty-four feet down in what is evidently 
 the true till of the region. 
 
 In Hamilton county, Ohio, the late Colonel Charles 
 Whittlesey reported thirty-five wells containing muck-beds, 
 leaves, or timber, from three hundred to five hundred feet 
 above the Ohio River.f That at New Burlington is certainly 
 in till. 
 
 In Highland county. Professor Orton reports many cases 
 of the occutrence of such vegetable deposits. In the village 
 of Marshall, " eleven wells out of twenty reached a stratum 
 of vegetable matter with leaves, branches, roots, and trunks 
 of trees." Marshall is on the very limit of the glaciated 
 region. Similar instances were reported to me in the south- 
 ern part of Highland county and in Clermont county. 
 
 In Eoss county, near Lattas, Mr. J. M. Connell reported 
 to me finding wood in a well, situated very near the extreme 
 limit of glacial action, and where it could not possibly have 
 been brought into position by means of water. The locality 
 is four hundred and twenty-five feet (barometer) above the 
 valley, just to the north, near Frankfort, and five hundred 
 and twenty-five feet above the valley of the Scioto River at 
 Chillicothe, ten miles to the east. The till is massed up 
 against and upon the margin of a rocky plateau, here facing 
 the north, in great quantities. The well described was in 
 this marginal till upon the highest land, and passed through 
 twelve feet of yellow clay, then through three or four feet 
 of blue clay, then ten feet of yellow clay, then gravel for 
 five feet. About thirteen feet below the surface there was 
 
 * "Geological Report of Indiana," 1875, p. 172. 
 
 f "Smithsonian Contributions to Knowledge," 1869, pp. 13, 14. 
 
THE DATE OF THE GLACIAL PERIOD. 603 
 
 found a log of wood three or four feet long and about three 
 inches in diameter. This was in the blue clay, and was ac- 
 companied with traces of muck. 
 
 There is not space to mention the many other, places 
 where wood is reported in the modified drift filling what are 
 perhaps preglacial channels serving as outlets of the melting 
 glacial torrents, and which may therefore have been trans- 
 ported a long distance from their native place. One such 
 was reported to me in the valley of Raccoon Creek, in Gran- 
 ville, Licking county, Ohio, and but a few miles from the 
 glaciated border. This was found ninety-fom- feet below the 
 surface of the terrace, which would bring it about forty feet 
 below the present bed of the stream. A few miles farther 
 up in this same valley so many red-cedar logs were formerly 
 found beneath the glacial terraces along the valley, and the 
 wood was so fresh, that a flourishing business was for a while 
 carried on in manufacturing household utensils from them. 
 Red cedar is not found in that region now, and these logs 
 are probably of the same period with those described as 
 found in true glacial till in Butler county, and which are so 
 fresh as to preserve still the peculiar odor of the wood. 
 
 Professor Collett reports that all through that portion of 
 southwestern Indiana included within the glacial boundary 
 there are found, from sixty to a hundred and twenty feet be- 
 low the surface, peat, muck, rotted stumps, branches and 
 leaves of trees, and that these accumulations sometimes occur 
 through a thickness of from two to twenty feet. 
 
 We may mention, also, as probably connected with the 
 period of the ice-dam at Cincinnati, the well-preserved or- 
 ganic remains found in the high-level terraces of various trib- 
 utaries of the upper Ohio. In the vicinity of Morgantown, 
 Professor I. C. White, as already noted, reports that, in the 
 terraces which he connected with the period of the Cincinnati 
 ice-dam, the leaves of our common forest-trees are most beau- 
 tifully preserved some distance below the surface, and that 
 logs of wood in a semi-rotten condition were encountered 
 seventy feet below the surface. At Carmichaels, in Wash- 
 
604 THE lOE AOS m NORTH AMERICA. 
 
 ington county, Pa., a log of wood was also reported to me 
 as found in a situation similar to that described by Professor 
 White, buried thirty feet in the sand of a corresponding 
 high-levcel terrace some miles back from the present bed of 
 the Monongahela. Wood was also reported to me as found 
 in a similar situation in terraces two hundred and fifty feet 
 above the Alleghany River at Parker, Pa. The terraces 
 there are many miles outside the glacial limit, but by their 
 granite pebbles are unmistakably connected with the Glacial 
 period. The wood was reported as dug from quicksand in 
 a well two miles east of the river, and two hundred and fifty 
 feet above it. 
 
 Another instance of wood which has been preserved in a 
 deposit of the Glacial age is worthy of more minute descrip- 
 tion. In this case I have the advantage of having found it 
 myself. The locality is that of Teazes valley, Putnam county, 
 W. Va. This valley runs from the Kanawha River a little 
 below Charleston to the Ohio at the mouth of the Guyan- 
 dotte near Huntington. The valley, as already described,* is 
 clearly enough a remnant of early erosion, when the water 
 of the upper Kanawha took that course to join the Ohio. 
 The valley is very clearly marked, being about a mile wide, 
 and from two hundred to three hundred feet lower than the 
 hills on either side, and having a remarkably level fioor 
 throughout the greater part of its course. The bottom of • 
 the valley is filled throughout with a deposit of river-pebbles 
 covered many feet with a mixture of sand and clayey loam. 
 In some places this loam is from thirty to forty feet deep, 
 extending for several miles without interruption, as at Long 
 Level, about the middle of the valley.f Here a section about 
 half a mile long and twenty-five feet deep shows at the top 
 a stiff stratum of clay containing wood at a depth of seven 
 feet. Immediately below is sand containing much iron, and 
 cemented together by the infiltrations of the ore. The strar 
 tum above, containing the wood, had never been disturbed, 
 
 * See p. 379. f See Fig. lll.on p. 380. 
 
THE DATE OF THE GLACIAL PERIOD. 605 
 
 and the wood (a small specimen of a knot of some coniferous 
 tree) is remarkably fresh in its whole appearance. It is 
 scarcely possible that it should have remained in such a posi- 
 tion during the immense period supposed by Mr. CroU to 
 have elapsed since the glacial age. 
 
 Many of these cases of subglacial vegetable accumula- 
 tions are beneath or in deposits of the very earliest portion 
 of the glacial period. Unquestionably of this age are those 
 found in Jackson, Jennings and Jefferson counties, Indiana, 
 and those found by Professor I. C. White in the terraces of 
 the Monongahela River, which are now correlated with the 
 earliest stages of the ice advance to the water-shed between 
 the Great Lakes and the Ohio River. 
 
 Farther north, notably in Mower Coimty, Minnesota, a 
 stratum of peat from eighteen inches to six or eight feet in 
 thickness, with much wood, is very uniformly encountered 
 in digging wells, the depth varying from twenty to fifty feet. 
 "From all accounts it (the peat stratum) appears to be em- 
 braced between glacial deposits of gravelly clay, and it 
 seems to mark a period of interglacial conditions when 
 coniferous trees and peat-mosses spread over the country . . 
 There are extensive marshes now existing in northern Min- 
 nesota, mainly covered with ericaceous plants, with some 
 cedar and tamaracks that are forming immense peat deposits. 
 With an increase of the amount of moisture in the air such 
 peaty acciunulations would spread over much higher levels. 
 A return of glacial conditions would bury such marshes be- 
 low the deposits that are known as drift."* 
 
 The observations of Professor Tarr upon the burial of 
 forests and peat bogs by the recent advance of glaciers in 
 Alaska are deserving of the most careful consideration in our 
 interpretation of the significance of the facts which are being 
 here detailed. 
 
 •N. H. Winchell in "Geology of Minnesota," vol. i of "Final Re- 
 port," p. 363. 
 
606 
 
 THE ICE AdE IN NORTH AMERICA. 
 
 ■'Along both the Atrevida ami the Malaspina glacier mar- 
 gins, the glacier and glacial deposits are advancing in forested 
 regions and overspreading old soils, peat beds, and forests. 
 When the process of present change is at an end there will 
 be in this region soil beds and plant beds interbedded with 
 glacial deposits, and all as the result of a sudden change in 
 glacier-margin conditions. It requires no elaboration of this 
 subject to make it clear that here is a hint of great significance 
 in the interpretation of pleistocene deposits. In view of 
 such phenomena as those described above it is evident that t he 
 interpretation sometimes placed upon plant beds and soil beds 
 intercalated in jileistocene deposits — namely, that they prove 
 
 Fig. 1.54 — Forest lately dNtnrlied and at:.out to he overwhelmed by an advancing A la.s lean 
 glacier. (Photo by Gilbert,) 
 
 separate glacial epochs — can hardly stand without the support 
 of other and convincing evidence that the plant or soil bed 
 interval was of long duration."* 
 
 All this is in the region where the natural drainage is to the 
 south; but, upon entering the northern water-shed, especially 
 in the area now covered by the deposits of Lake Agassiz, in- 
 terglacial deposits would seem necessarily to imply that the 
 
 ^ *R. S.Tarr and B. S. Butler, "The Yakutat Bay Region, Alaska," 
 "U. S. Geological Survey," "Professional Paper," 64, pp. SO, 87. 
 
THE DATE OF THE GLACIAL PERIOD. 607 
 
 ice had melted back sufficiently to reopen the natural drain- 
 age lines of the Eed Eiver Yalley into Hudson Bay. Mr. 
 Upham confesses that beds of vegetal deposit which are 
 both underlaid and overlaid by till are very rarely found in 
 northern Minnesota. Still, he supposes some such are found, 
 and gives an exhaustive list of instances.* The two which 
 he mentions as being in the area of Lake Agassiz are encount- 
 ered in digging wells, first, at Barnesville, Clay county, where 
 twelve feet of till was penetrated, then one foot of quicksand 
 " containing several sticks of tamarack up to eight inches in 
 diameter ; second, in "Wilkin county, where the record is that 
 tiU occupied the Hrst eight feet, then a layer of gray sand 
 one half an inch in thickness, then a much harder lower till 
 for eighteen feet, which was underlaid by sandy black mud 
 containing many snail-shells. But these two cases hardly 
 seem sufficient to estabhsh the theory, while the correspond- 
 ing cases adduced by the Canadian geologists farther north 
 are not described with sufficient minuteness to render their 
 meaning unequi vocal. f 
 
 Another class of phenomena bearing on the questions of 
 the discontinuity and date of the great Ice age is to be found 
 in the inclosed lake-basins lying between the Rocky Mount- 
 ains and the Sierra Nevada, near the fortieth parallel. Nu- 
 merous salt lakes now occupy this region. But it is evident, 
 even upon hasty examination, that these are but insignificant 
 remnants of those which formerly occupied it. Great Salt 
 Lake is estimated to have contained at one period four hun- 
 dred times its present volume of water. The terraces mark- 
 ing its former limits are very distinctly visible, and are nine 
 hundred feet above its present level. Lake Mono has several 
 distinct terraces, the highest of which is six or seven hun- 
 dred feet above the present level. Pyramid and North Car- 
 son Lakes, in Nevada, are but the remnants of an immense 
 salt lake extending from the Oregon boundary to latitude 
 
 * "Minnesota Geological Report for 1879," p. 48. 
 
 ■f " Report of Progress, Geological Survey of Canada, 1882-'84," p. 414, C. 
 
608 
 
 THE ICE AGE IN NORTH AMERICA. 
 
 38° 30' south, a distance of two hundred and sixty miles. 
 The Central Pacific Eailroad is built through the bed of this 
 lake for one hundred and sixty five miles, from the vicinity 
 of Golconda to that of Wadsworth. This ancient lake has 
 been carefully surveyed and described by Mr. I. C. Russell, 
 of the United States Geological Survey,* and has been named 
 
 Fig. 1S5.— Sketch map of the Pacific coast, showing the ontllnes of the ancient lakes Bon- 
 neville and Lahontan. (Le Conte.) 
 
 * " Third Annual Report of the United States Geological Survey," pp. IW" 
 236, and " Monograph XI," 188S. 
 
THE DATE OF THE GLACIAL PERIOD. 609 
 
 Lake Lahontan, as that of which Great Salt Lake is the rem- 
 nant was named Lake Bonneville, after the first explorers of 
 the region. These basins have now no outlet to the sea. 
 That of Lake Lahontan never had any; but, if the relative 
 levels were the same at former times as now. Lake Bonne- 
 ville at its greatest ejctent poured through Snake River into 
 the Colmnbia. 
 
 During the year 1890 Mr. Gilbert published the first volume 
 of his monograph upon Lake Bonneville — the ancient enlarge- 
 ment of Great Salt Lake, Utah — ^to which reference has just 
 been made above. Mr. Gilbert estimates that at its maxi- 
 mima stage the area of this lake was 19,750 square miles — ^that 
 is, about ten times the present size of Great Salt Lake — and 
 that its maximum depth was one thousand and fifty feet, as 
 compared with about forty feet at present. The climatic 
 changes indicated by the. studies of this ancient lake cor- 
 respond closely with those indicated by Mr. Russell's study 
 of Lake Lahontan as detailed on page 607. Early in post- 
 tertiary times there was a great rise in these lakes, though 
 not sufficient by ninety feet to reach the passage through 
 the Port Neuf River into the Snake. This first rise was fol- 
 lowed by a long epoch of desiccation, during which it is prob- 
 able the lake entirely disappeared. This inter-lacustrine epoch 
 was a long one, as is indicated by the extent of the gravel 
 deposits which were then laid down. After this there was a 
 second rise, in which the water attained the height of the pass- 
 age from the Cache Valley to the Port Neuf, and then rapidly 
 " cut a channel three hundred and seventy-five feet deep in the 
 alluvium to a sill of limestone." At this level (about six hun- 
 dred feet above the Great Salt Lake) the water was held for a 
 long time, forming what is known as the Provost shore-line. 
 During the period of the Provost shore-line, glaciers descended 
 from the Wahsatch Mountains, and left their moraines near 
 the margin of the lake. 
 
610 THE ICE AGE IN NORTH AMEBIC A. 
 
 la searching for an explanation of the former increase in 
 size of these bodies of water, the conditions of the Glacial 
 period naturally present themselves as furnishing an ade- 
 quate cause. Glaciers, however, never occupied much of the 
 territory, being found only to a limited extent in the border- 
 ing mountain-ranges. But the proximity of the glaciated 
 region, and, indeed, the general conditions favoring the pro- 
 duction of the Glacial period in North America, would be 
 ample to produce the temporary enlargement of these lakes. 
 A slight increase in precipitation, or a slight diminution of 
 temperature, would either of them cause a rise in the water 
 until the balance should be readjusted between the rainfall 
 and the evaporation. 
 
 It would seem that there is here also a significant record 
 of an interglacial epoch, for the lakes have had two periods 
 of increase, with an arid period intervening. During the 
 first rise of the lakes, sediment to the extent of one hundred 
 and fifty feet in thickness was deposited. There was then a 
 dry period, in which the lakes were reduced to their present 
 dimensions, or even smaller, when these first deposits were 
 subjected to a period of erosion by surface streams, and partly 
 covered with gravel. There was also upon it a deposit of 
 great quantities of compact stony tufa precipitated from 
 waters saturated with calcium carbonate. After the period 
 of low water there was a subsequent reflooding of the basin, 
 which reached a horizon thirty feet higher than the first. 
 During this rise a deposit of thinolite took place, and of otliei 
 substances whose position and character serve to note the 
 changes. Subsequent to this rise the evaporation proceeded 
 at an increased rate until the basins were completely desic- 
 cated, and only began to refill within a period wliich Mr. 
 Russell estimates to be less than three hundred years. All 
 this, however, might have occurred within the space of a few 
 thousand years, and does not, independently of other evidence, 
 go far to establish the complete duahty of the Ice age. 
 
 As to the date of the expansion of these lakes, Mr. Rus- 
 sell expresses it as his opinion that "the last desiccation oc- 
 
THE DATh OF TEE GLACIAL PERIOD. 611 
 
 curred certainly centuries, but probably not many thousands 
 of years ago." * This opinion is sustained by the fact that 
 the erosion of present streams in these old beds is slight, and 
 by the fact that in the canons of the high Sierra, which were 
 once occupied by glaciers, "the smooth surfaces are still 
 scored with fine, hair-like lines, and the eye fails to detect 
 more than a trace of disintegration that has taken place since 
 the surfaces received their polish and striation. ... It seems 
 reasonable to conclude that in a severe climate like that of 
 the high Sierra it [the polish] could not remain unimpaired 
 for more than a few centuries at the most." To the same 
 effect is the testimony of Mr. Gilbert as to the date of the 
 last great extension of Lake Bonneville, of which he says : 
 " The Bonneville shores are almost unmodified. Intersect- 
 ing streams, it is true, have scored them and interrupted 
 their continuity for brief spaces ; but the beating of the rain 
 has hardly left a trace. The sea-cliffs still stand as they first 
 stood, except that frost has wrought upon their faces so as to 
 crumble away a portion and make a low talus at the base. 
 The embankments and beaches and bars are almost as perfect 
 as though the lake had left them yesterday, and many of 
 them rival in the symmetry and perfection of their contours 
 the most elaborate work of the engineer. There are places 
 where bowlders of quartzite or other enduring rock still re- 
 tain the smooth, glistening surfaces which the waves scoured 
 upon them by dashing against them the sands of the beach. 
 
 " When this preservation is compared with that of the low- 
 est tertiary rocks of the region — the Pliocene beds to which 
 King has given the name Humboldt — the difference is most 
 impressive. The Pliocene shore-lines have disappeared. 
 
 •* The deposits are so indurated as to serve for building- 
 stone. They have been upturned in many places by the up- 
 lifting of mountains. Elsewhere they have been divided by 
 faults, and the fragments, dissevered from their continuation 
 in the valley, have been carried high up on the mountain- 
 
 * " Monograph XI," p. 273. 
 
612 THE ICE AGE IN NORTH AMERICA. 
 
 fianlis, where erosion has carved them in typical mountain 
 forms. . . . The date of the Bonneville flood is the geologic 
 yesterday, and, calling it yesterday, we may without exag- 
 geration refer the Pliocene of Utah to the last decade the 
 Eocene of the Colorado basin to the last century, and re- 
 legate the laying of the Potsdam sandstone to prehistoric 
 times."* 
 
 Mr. Gilbert believes that all this is attributable to suc- 
 cessive elevationsof the region, with an intervening subsidence. 
 The evidence of a post-tertiary elevation is found "in the 
 deeply submerged channel near Cape Mendicino," while the 
 proofs of a subsequent depression " are supplied by the marine 
 terraces of the Columbia and Fraser basin, and by the post- 
 tertiary beds of Ihe California coast recently described by 
 Dall as rising gradually toward the south until at Monterey 
 and southward they are about six hundred feet above the 
 sea-level. The uplifting of the Wahsatch range 
 
 is shown to be still in progress by post-Bonneville fault- 
 scraps." Mr. Gilbert's study of the horse-remains found in 
 the region would assign them to the period of "the upper- 
 most of the Lahontan and Bonneville beds," thus transferring 
 their geological horizon from the late tertiary to the latter 
 part of the glacial period. 
 
 It is interesting to note, in connection with these old 
 lake-basins, that the Dead Sea in Palestine probably has a 
 similar relation to the development of glaciers in the Le- 
 banon Mountains, and Russell is of the opinion that the 
 gravel-deposits reported at various elevations about it are, 
 like those of Lakes Bonneville and Lahontan, records of 
 the Glacial period, f 
 
 My own investigations upon the glacial deposits of the 
 Lebanon Mountains, however, showed that there had never 
 been any glaciers reaching the head-waters of the Jordan 
 Valley; but there was a glacier descending from the highest 
 
 *"Seeond Annual Report of the U. S. Geological Survey," p. 188. 
 t "Jordan-Arabah and the Dead Sea, "Geological Magazine," 
 
 Tol. 5, pp. 337, 387. 
 
THE DATE OF THE GLACIAL PERIOD. 613 
 
 summit of the mountains about thirty miles northeast of 
 Beirut and depositing an extensive moraine upon which the 
 present grove of the Cedars of Lebanon are growing. The 
 height of the summit is a little over 10,000 feet, and the glacier 
 descended to the level of 5,000 feet above the sea. The mo- 
 raine is about three miles broad at the foot, and extends five 
 miles b^ck toward the summit, and is several hundred feet 
 thick at its termination. Though not directly connected 
 with the Jordan Valley the climatic conditions accompanying 
 the formation of this glacier doubtless extended a long dis- 
 tance in that direction and so may accoiint for the enlarge- 
 ment of the Dead Sea indicated by the abandoned shore- 
 lines, the most persistent of which is 650 feet above its present 
 level. (See "Records of the Past," July, 1906, pp. 195-204.) 
 
 Such are, in brief, the considerations which seem to make 
 it proper to hesitate before recognizing the theory of discon- 
 tinuous pleistocene epochs in America as an established 
 doctrine to be taught. The most of the facts adduced to 
 support the "theory of distinct epochs are capable of explana- 
 tion on the theory of but one epoch with the natural oscil- 
 lations accompanying the retreat of so vast an ice-front. It 
 seems more likely that the retreat from the extreme border 
 of the glaciated area to the line of the moraines of the several 
 later glacial epochs was analogous to that from one to another 
 of the successive twelve or thirteen receding concentric lines of 
 moraine appearing on our general map and on that of 
 Minnesota made from the latest reports, than that successive; 
 glacial advances should so nearly duplicate the first as it ia 
 made to do on the other theory. 
 
 After a painstaking discussion of the whole subject. 
 Professor Prestwich expresses it as his opinion that — 
 
 The time required for the formation and duration of the 
 great ice-sheets in Europe and America (the Glacial period) 
 need not, after making all allowances, have extended be- 
 yond fifteen thousand to twenty-five thousand years, instead 
 
614 THE ICE AGE IN NORTH AMERICA. 
 
 of the one hundred and sixty thousand years or more which 
 have been claimed. 
 
 The adoption by some of a term of eighty thousand 
 years for the post-Glacial period has been very much the 
 result of the belief that no shorter time would account for 
 the excavation of the valleys supposed to have been formed 
 during this period, on the assumption of a "uniformitarian" 
 rate of denudation. This rate, based on observations made 
 at the present time, always seemed to me open to grave 
 objections, and in this belief subsequent experience has 
 confirmed me. . . . and I would for the same reasons limit 
 the time of the so-called post-Glacial period, or of the 
 melting away of the ice-sheet, to from eight thousand to 
 ten thousand years or less.* 
 
 Summary. — The terrestrial facts brought to light as 
 clearly bearing on the question of the date of the glacial era 
 are much more numerous tlian they have heretofore been 
 supposed to be. Scarcely more than a beginning has been 
 made in their collection and interpretation ; but, as far as we 
 have gone, the investigation has been most interesting and 
 suggestive. For the most part these facts imply a later date 
 for the Glacial period than the current astronomical theory 
 would admit, and so far they go to disprove that theory. 
 
 The glaciated area seems a vastly newer country than 
 the unglaeiated. In the glaciated region the waterfalls have 
 hardly more than begun to recede ; the valleys and gorges 
 are both narrower and shallower than in the unglaeiated por- 
 tion of the country ; the lakes and kettle-holes are yet unfilled 
 with sediment, and their outlets have not yet to any great 
 extent lowered the drainage lines ; the striated rocks have 
 resisted disintegration to a remarkable degree during post-gla- 
 cial times, and the moraines and kames have retained their 
 original forms with little signs of erosion. T^Tiagara Falls 
 and the Falls of St. Anthony can neither of them be over 
 ten thousand years old. The waves of Lake Michigan can 
 
 * See Prestwich's " Geology," vol. ii, pp. 633, 534. 
 
THE DATE OP THE GLACIAL PERIOD. 
 
 615 
 
 not liave washed its shore for a much longer time, and the 
 smaller lakes and kettle-holes of New England and the North- 
 west can not have existed for the indefinite periods some- 
 times said to have elapsed since the glacial era, while eternity 
 itself is scarcely long enough for the development of species 
 if the rate of change is no greater than is implied if man and 
 his companions both of the animal and vegetable kingdom 
 were substantially what they are now as long ago as the date 
 often assigned to the great Ice age. 
 
 But while approximate limits are already set to glacial 
 chronology, the held is still open for an indefinite amount of 
 painstaking inquiry. Local observojs may now profitably 
 spend as much time upon a single river-valley or in a single 
 county as has yet been spent upon the whole field between 
 Cape Cod and the Mississi])pi. 
 
 Fig. 156 — Bowlder bed at Pocatello, Idaho, where the Port Neuf river debouches upon 
 the Snake river plain. These bowlders were brought down to tlielr present position 
 by the torrential floods which followed the overflow ol Lake Bonneville, described 
 on pages 609 and 704. 
 
CHAPTER XXI. 
 
 MAX AXI) TUE GLACIAL PEEIOD. 
 
 When, in 1863, Sir diaries Ljell piiblislied his great 
 work upon " Tlie Auti(iiiity of Mau," the general pnbhc was 
 somewhat surprised to tind that one hundred and sixty pages, 
 or ahnost one third of the entire volume, was devoted to a 
 discussion of glacial phenomena. This course was justified 
 by the fact that rough-stone implements, undoubtedly of 
 human manufacture, had recently lieen found in deposits 
 
 supposed to be of 
 glacial age in noi th- 
 ern France and 
 southern England, 
 making the question 
 of the antirpiity of 
 man one no longer 
 of mere history or 
 arcliEeology, but of 
 glacial geology. A 
 furtlier reason for 
 the prominence giv- 
 en to the discussion 
 of purely glacial 
 questions in Sir 
 Charles Lyell's work 
 was the comparative 
 ignorance, at that 
 time, of the cliaracter, extent, and significance of glacial phe- 
 nomena. The discussions running through the previous 
 
 Fig. 157. — Typical collection of paleolithic ilnplemt'nt^;. 
 reduced in pliotoirraph to one eighth natural pize. 
 The four in the Iowit row are of ar^rillite from the 
 gravel in Trenton, New Jersey. The small one. a lit- 
 tle above the lower row is from Mon.stier. France. 
 The large one in the middle row is from Amiens. 
 France. The two at the left of it are from Fiance. 
 The one at the right is from upner Egypt. These 
 are all of flint. The four in the upper row. a core of 
 flint and flakes of flnit. 
 
MA2^ AND THE GLACIAL PERIOD. 
 
 617 
 
 readily 
 
 already 
 
 -Reverse side of the implements sliowii in tlie precod- 
 iiiL' limire. 
 
 chapters of the present volume prepare the way for 
 understanding even a summary statement of the facts 
 discovered con- 
 necting man 
 with tiie Gla- 
 cial period in 
 North Ameri- 
 ca. We may, 
 therefore, with- 
 out further pre- 
 liminaries, at 
 once address 
 ourselves to the 
 subject, and de- 
 scribe the con- 
 ditionsinwhich 
 implements of ^Fig- iss.- 
 human manu- 
 facture have been found in the glacial deposits on this con- 
 tinent. 
 
 At the outset two questions arise in the discussion : 1. 
 "Whether the implements found are really artificial and gen- 
 uine. 2. Whether the deposits in which they occur really 
 belong to the Glacial period. 
 
 1. That the implements are of human origin is evident 
 from close inspection, and comparison with natural frag- 
 ments. Flint and some other species of stone are specially 
 adapted for tlie manufacture of implements, because of their 
 hardness, and of tiie facility with which flakes can be struck 
 from them so as to leave a sharp, cutting edge. Many nat- 
 ural forms of flint can be appropriated as useful tools with- 
 out modification. The action of frost upon a flint nodule, 
 or the accidental falling of a stone upon it, may produce a; 
 sharp-edged fraginent of convenient size for use. But the 
 proof of human workmanship consists in a series of fractures, 
 of such character and so arranged that they irresistibly indi- 
 cate design. One prominent feature of an artificial flake is 
 
618 THE ICE AGE IN NORTE AMERICA. 
 
 the so-called "bulb of percussion." When a sharp, well- 
 directed blow falls upon a flint nodule, the force distributes 
 itself in such a way that, in the immediate vicinity of the 
 blow, a slight hollow is made in the nodule, and the corre- 
 sponding bulb in the flake is shaped somewhat like the ball of 
 one's thumb, while the rest of the flake is straight and regu- 
 lar in form. It is possible that this bulb of percussion may 
 sometimes be made by the accidental falling of one stone 
 upon another ; but such an occurrence must, in the nature of 
 the case, be very rare, since the blow must be delivered at 
 exactly the right point and at the proper angle, in order to 
 produce the right result. The chances are exceedingly small 
 that such a blow should be delivered except by design. 
 
 As to the arrangement of the fractures, the evidence is 
 even more conclusive. A simple cutting edge may readily 
 be formed by natural forces ; but, in the implements that 
 are regarded a;s of human origin, the arrangement of the fract- 
 ures producing the cutting edge is so complicated as to pre- 
 clude the supposition that they are undesigned. Nor does it 
 require many secondary chippings to establish the artificial 
 origin of an implement. A half-dozen subsidiary chippings 
 on a natural flint pebble, serving to bring it into a symmetry 
 such as wonld serve the purpose of a human being, is evi- 
 dence enough. A trained eye has no difficulty in distin- 
 guishing, at a glance, between natural forms and artificial 
 forms. The loose statements asserting that there is 'occasion 
 for grave doubt as to whether the mass of so- called palaeo- 
 lithic implements are really implements can only be made, 
 and be believed, by those who have given little personal at- 
 tention to the subject. 
 
 That I may not seem to place too much confidence in 
 my own judgment in this all-important matter, I have 
 thought it best to secure the opinion, concerning the imple- 
 ments of which this chapter treats, of one who has had ample 
 opportunity to examine them and compare them with those 
 from other parts of the world, and whose authority would 
 be second to that of none. I therefore addressed a letter 
 
MAN AND THE OLAGIAL PERIOD. 619 
 
 to Professor Henry W. Haynes, of Boston, requesting his 
 opinion on the subject. His reply I will, with his consent, 
 reproduce.* 
 
 Boston, January SS, l!889. 
 Dear Pbofbssor Weight : You ask for my opinion in 
 regard to the artiflcial character of the quartz fragments dis- 
 coTered by Miss Babbitt, at Little Falls, Minn., as well as of 
 the argillite objects discovered by Dr. Abbott, at Trenton, 
 N. J., and those still more recently obtained by Dr. Metz and 
 Mr. Cresson. In replying to your inquiry I must premise by 
 stating that, although I have had abundant opportunity of 
 studying all these different objects, I have only visited one of 
 the localities where they were found — that is Trenton, N. J. — 
 where, as you know, I was accompanied by yourself, Professor 
 Boyd Dawkins, and the late Professor Henry Carvill Lewis, in 
 my examination of the region ; but I had previously visited 
 many localities in Europe, where palaeolithic implements have 
 been discovered ; and I have myself found many. Several 
 years of study in that country have made me familiar with 
 the cleavage of flint, and the method of fabricating rudely 
 chipped implements. Subsequently, in this country, for a 
 still longer period, I have given much attention to the tools 
 and weapons of the Indians, and the different materials of 
 
 * I would remark that Professor Haynes's private collection of palseoliths is 
 one of the largest in this country, and abounds in representatives from every 
 locality where they have been found. The following is a list of bis publications 
 upon the subject : Silex AchenUeus de I'Egypte, " Bull, de la Soc. d'Anthrop. 
 de Paris," 3d ser., vol. i, p. 339 ; " The Fossil Man," " Popular Science Monthly," 
 July, 1880, p. 350; "The Egyptian Stone Age," "Nation," January 27, 1881'; 
 " Discovery of Palaeolithic Implements in Egypt," '' Memoirs of the American 
 Academy of Arts and Sciences," vol. x, p. 367 ; " The Argillite Implements," etc. 
 "Proceedings of the Boston Society of Natural History," vol. xxi, p. 132; "The 
 Palaeolithic Man," " American Antiquarian," vol. vi, p. 137 ; " The Stone Age in 
 Prehistoric Archaeology," " Science," vol. iv, pp. 469, 622 ; " Man in the Stone 
 Age," " Science," vol. v, p. 43 ; " The Bow and Arrow unknown to Palaeolithic 
 Man," "Proceedings of the Boston Society of Natural History," vol. xxiii, p. 
 269 ; " Palaeolithic Man in London and its Neighborhood," " Science," vol. ix, 
 p. 221 ; " Opinion on Palaeolithics," " American Antiqu.arian," vol. a, p. 126 ; 
 " The Prehistoric Archaeology of North America '' ; " Narrative and Critical 
 History of America." vol. i. pp. 329-368. 
 
620 THE ICE AGE IN NORTH AMERICA. 
 
 which they were fashioned, in a great many different localities. 
 I think, therefore, I have gained an acquaintance with the 
 character of the fracture of very many different kinds of stone, 
 which have been broken by man intentionally for his use as tools. 
 I say this, because I have always been in the habit of compar- 
 ing and contrasting such broken stones with those whose fract- 
 ure had been occasioned by different natural forces, so that 
 I might learn the resemblances and the differences between 
 them. This is a subject which it is difficult to treat of satis- 
 factorily in writing, as it is so much an affair of ocular dem- 
 onstration. These little minute differences and peculiarities 
 are very palpable, when they are pointed out, although a geolo- 
 gist, or a mineralogist, who is perfectly familiar with the ma- 
 terial, but who may have had little or ho training as an archae- 
 ologist, may have failed to notice them. The whole subject 
 is one solely for the judgment of the expert ; and when a 
 heap of broken stones, characterized by a general external re- 
 semblance, has been submitted to the determination of several 
 trained archaeologists, as I have often seen done in Europe, 
 there has been no difference of opinion among them as to 
 which were natural and which were artificial forms. Of course, 
 if the broken stones have been afterward subjected to the action 
 of running water, so as to produce a general wearing away of the 
 edges of the fractures, the difficulty of discriminating becomes 
 much greater. In such cases only a very practiced eye can de- 
 cide, and the opinion of any man, however eminent he may 
 be in other departments of knowledge, who has not had great 
 archaeological experience, is practically worthless. 
 
 It was in the autumn of 1880 when we visited Trenton, 
 and at that time I found a few palaeoliths there myself ; after- 
 ward Dr. Abbott gave me quite a collection of his own find- 
 ing, which I have had ever since in my possession, and have 
 continually studied. So in repeated instances have I examined 
 his great collection in the Peabody Museum. At a meeting 
 of the Boston Society of Natural History, in January, 1881, 
 I expressed my conviction as to the artificial character of 
 these argillite implements, notwithstanding the fact that the 
 coarseness of their material precludes their ever equaling in 
 workmanship the flint implements of Europe. My subsequent 
 
MAJr AND THE GLACIAL PERIOD. 621 
 
 study of the same and other objects from that locality has only 
 seryed to strengthen the opinion I then expressed. 
 
 The quartzes discoyered by Miss Babbitt I first saw in the 
 autumn of 1883, when she forwarded a box of them for my 
 inspection. The following summer she sent me another lot 
 of them on deposit ; both of these have been in my possession 
 eyer since, and haye been repeatedly studied by me. I haye 
 also examined the collection she sent to the Peabody Museum. 
 I should judge that I haye thus had at least a hundred and fifty 
 of these pieces of quartz brought under my careful scrutiny. 
 Miss Babbitt had no knowledge of archaeology, and her fanci- 
 ful speculations in regard to the supposed use that had been, 
 or might have been, made of certain fragments, which she dig- 
 nified with the name of types, have tended to obscure the real 
 presence among them of some well-marked examples of palaeo- 
 lithic implements. I wrote her my opinion in regard to them, 
 and a portion of my letter was printed by her in connection 
 with her articles on "Vestiges of Glacial Man in Minnesota," 
 in the June and July numbers of the " American Naturalist " 
 for 1884. In this I stated that " some of them I believe to be 
 implements ; many are only chips struck off in shaping imple- 
 ments, and refuse pieces left from such work ; many are natural 
 forms, and one or two rolled pebbles. ... I trace clearly upon 
 your implements such a preparation of them (i. e., by having 
 had most of their projections battered ofE by another stone) 
 for holding them in the hand. Many of yours bear evident 
 marks of use in the worn condition of portions of their edges 
 or of their points." All my subsequent study of them has 
 tended to confirm this opinion, and I can only repeat my 
 assured conviction that these rudely fashioned implements, and 
 the fragments that were fonnd with them, whose edges are 
 still as sharp as when they were first struck off, are the " prod- 
 uct of an intentional breaking by the hand of man and not 
 the result of natural causes." 
 
 It is important to notice that among the hundreds of 
 palaeolithic implements discovered by Dr. Abbott, at Trenton, 
 a few made of quartz are so absolutely similar to those found by 
 Miss Babbitt, and now either in my possession or at the Peabody 
 Museum, that it would be impossible to distinguish them apart. 
 
622 TEE ICE AGE IN NORTH AMERICA. 
 
 The implements discovered by Dr. Metz and Mr. Cresson, 
 and now also in the Peabody Museum, are as palpable human 
 tools as any I ever saw, although, on account of the inferior 
 quality of the material of which they are made, they are not 
 equal in excellence to similar objects of like age in Europe. 
 I can not conceive of any one, who has a proper acquaintance 
 with the subject, entertaining a moment's question as to their 
 artificial character. 
 
 By this frank expression of my conviction, I have en- 
 deavored, as best I can, to answer your questions, and remain, 
 
 Sincerely yours, 
 
 Henky W. Hatnes. 
 
 A still further question with regard to these implements 
 relates to their genuineness. Their present commercial value 
 offers temptation for their forgery, and there can be no doubt 
 that hundreds of implements of the very earhest type have 
 been made to order and sold to unsuspecting collectors. 
 Still, however perfect these forgeries may be in form, only 
 the inexperienced and the unwary can be deceived by them. 
 There are certain chemical changes affecting the superficial 
 aspect of an implement which time only can produce. A 
 fresh flake can readily be distinguished by a practiced eye. 
 As yet not enough is known of the rapidity with which 
 weathering takes place under stated conditions, to make it a 
 basis for chronological calculation ; but the difference be- 
 tween a very ancient implement and a very recent one is 
 easily enough detected. It is a significant fact early observed, 
 and supported by all recent discoveries (if we except those 
 in California, of which further mention will be made), that 
 in America as in Europe the implements found in glacial 
 deposits are all of a peculiar type. None but implements of 
 stone have been found in these deposits ; and of the stone 
 implements none are polished and smooth, but all are rude 
 in form and roughly flaked. From their evident antiquity, 
 as will be shown a little later, these rough stone implements 
 are called paloBoUthic (Grr. TraXato? "old," and \/^o?, 
 
MAN AND TEE GLACIAL PERIOD. 623 
 
 " Btone ") ; while the later stone implements are classified 
 as neolithic (Gr. veo?, " new," and XlBof, " stone "). 
 
 Palaeolithic implements are said to be old, however, not 
 because of any inelastic theory of evolution, implying that 
 people using rude arts always precede those who are more 
 skilled, bat the age of these implements as a class is deter- 
 mined by the fact that they have been found in imdisturbed 
 glacial deposits or under other geological conditions showing 
 their antiquity. Such implements are unquestionably older 
 than others found upon the surface ; and, in their case, the 
 evidence of great age is definite and conclusive, while the 
 antiquity of the implements found upon the surface is sub- 
 ject to more or less of doubt. If man inhabited the region 
 bordering upon the great ice-sheet when it extended to its 
 farthest limits, his implements should be found near the sur- 
 face of the ground outside those limits ; and such might be 
 of even greater age than those which are found in stratified 
 glacial deposits themselves. Also, as the ice receded, it is to 
 be expected that man would follow it in its slow recession 
 (as the Eskimo does to-day in Greenland) and that his imple- 
 ments would be lost upon the surface. How long he may 
 have continued thus to use implements of palaeolithic type 
 can not readily be determined. Mr. Thomas Wilson, of the 
 Smithsonian Institution, has already collected, or had reported 
 to him, many thousand implements of the palaeolithic type 
 found in various parts of North America. In almost all 
 cases these were found upon the surface, and there is no 
 means of determining their age except from their general 
 weathered appearance, as implements of the same forms have 
 been made and used all through the Stone age. 
 
 About the year 1860 interest in the subject of man's an- 
 tiquity received a new and definite impulse in connection 
 with the discoveries of Boucher de Perthes in northeastern 
 France. As long ago as 1841 this indefatigable investigator 
 discovered rudely fashioned stone implements in high gravel 
 terraces along the valley of the Somme at Abbeville. An 
 account of his discoveries was published in 1846. Little at- 
 
624 THE ICE AGE IN NORTH AMEBIGA. 
 
 tention was paid to the matter, however, until 1859, when 
 Dr. Falconer, Mr. Prestwich, Mr. Evans, Sir Charles Lyell^ 
 and other English geologists visited the locality, and brought 
 the discovery more fully to public attention. Full descrip- 
 tions may be found in the works of Sir Charles Lyell on 
 " The Antiquity of Man" * and Sir John Lubbock on " Pre- 
 historic Times." f 
 
 The river Somme is a small stream, about one hundred 
 miles in length, occupying a broad, deep trough, about a mile 
 in width at Abbeville, worn out of chalk formations. Upon 
 the sides of this trough, up to an elevation of something over 
 one hundred feet, there are remnants of gravel terraces^ 
 formed when the river flowed at a correspondingly higher 
 level than now. These terraces consist wholly of material 
 local to the Somme Valley, and not in any degree of foreign 
 drift. The implements found are imbedded in undisturbed 
 strata of this gravel. In connection with them, also, there 
 are found bones of many animals no'w extinct, those of the 
 Elejphas prindgenius being specially numerous. 
 
 Soon after the confirmation by these eminent authorities 
 of the important discoveries made by Boucher de Perthes, 
 examination showed that the same class of rudely formed 
 chipped stone implements occurred also in gravel- deposits in 
 southern England. The relation of these deposits to the 
 streams was similar to that of those in the valleys of north- 
 eastern France. Indeed, a discovery of palseoliths had been 
 made in England more than fifty years before, in the very 
 first years of the century ; but its importance was not sus- 
 pected until Boucher de Perthes's discoveries called attention 
 anew to the subject. Mr. John Frere had, in the year 1800, 
 described a collection of flints found at Hoxne near Diss, in 
 Suffolk, England, specimens of which were preserved in the 
 British Museum and in the collections of the Society of Anti^ 
 quaries. These proved to be of the same type with those 
 found at Abbeville, and the deposits are of corresponding 
 
 * p. 106 «< seq. f P. 342 et seg. 
 
MAN AND THE GLACIAL PERIOD. 625 
 
 character in the two places. Similar discoveries were also 
 made at various other places in southeastern England, the 
 most important being in the vicinity of Southampton and the 
 Isle of Wight. 
 
 When w6 come to examine these European deposits with 
 reference to their relation to the Glacial period, it must be 
 confessed that we enter a rather obscure iield. The region 
 in Europe in which palaeolithic implements have been found 
 imbedded in the gravel of river terraces is peculiar for its 
 limitation. In Great Britain none have been found north of 
 a line connecting the British Channel with the Wash, and 
 on the Continent these discoveries are all outside the direct 
 action of glaciers either from the Scandinavian or the Swiss 
 fields. Hence it will be seen that the problem is quite dif- 
 ferent from that which we shall presently study in America, 
 and is far more complicated. Still, the same rule holds good 
 in one country as in the other, that the higher terraces are 
 older than the lower, and there can be little doubt that the 
 terraces in which palseoliths are found are directly or in- 
 directly of glacial origin. But the data for estimating the 
 time which has elapsed since the deposition by glacial tor- 
 rents of the high-level gravels in the valley of the Somme 
 ■and in southern England are much less clear than in this 
 'country. 
 
 The year 1875 marks an epoch in the prehistoric archae- 
 ology of JSTorth America, since it was then that Dr. C. C. 
 Abbott's attention was first specially attracted to the imple- 
 ments of a palaeolithic type found in the neighborhood of his 
 residence in Trenton, N. J. Whether these implements were 
 from the surface, or from the gravel which underlies the city, 
 was at first uncertain, for they had then been found only in 
 the talus of the gravel-banks. But Dr. Abbott's residence 
 at Trenton enabled him during the succeeding year to give 
 attention to the numerous fresh exposures of the gravel 
 .made by railroad and other excavations ; and he was soon 
 rewarded for his pains by finding several chipped imple- 
 ments in undisturbed strata of gravel, some of which were as 
 
626 
 
 THE ICE AGE IN NORTH AMERICA. 
 
 much as twelve feet below the surface. 
 
 Fig. 159. — Face view of argillite implement, found by Dr. C. C. 
 Abbott, in 1876. at Trenton, New Jersey, in gravel, tliree 
 feet from face of bluff, and twenty-two feet from the sur- 
 face (No. 10,985). (Putnam.)* 
 
 Since that time he 
 has continued to 
 make similar 
 discoveries at 
 various inter- 
 vals. In 1888 
 he had already 
 found four hun- 
 dred implements 
 of the palaeolith- 
 ic type at Tren- 
 ton, sixty of 
 which had been 
 taken from re- 
 corded depths in 
 the gravel, two 
 hundred and fif- 
 ty from the talus 
 at the bluff fac- 
 ing the river, and 
 the remainder 
 from the surface, 
 or derived from 
 collectors who 
 did not record 
 the positions 
 or circumstances 
 under which 
 they were found. 
 In 1878 Profess- 
 or J. D. Whit- 
 
 * This cut, together with the following ones credited to him, Professor P. 
 W. Putnam has kindly furnished me, for use in advance of publication, from 
 his elaborate report upon the paleolithic implements in the Feabody Museum of 
 American Archaeology and Ethnology, Cambridge, Mass. The numbers in paren- 
 theses are those on the implements, and correspond to the catalogue of the 
 museum. The figaros are natural size. 
 
MAN AM) THE GLACIAL PERIOD. 627 
 
 iiey, with Mr. Lucien Carr, of the Peabody Museum, Cam- 
 bridge, visited Dr. Abbott, and they together found several 
 palaeolithic implements in the undisturbed gravel.* And 
 again, in 1879 and 1880, Professor F. Wo Putnam was with 
 Dr. Abbott when specimens /^ 
 
 were found in similar condi- / illWk 
 
 tions. Mr. Oarr describes the /// M 
 
 situation as follows : It was " in / Jffi 
 
 a fresh exposure made by a re- / iMtmBH 
 
 cent heavy storm, and was about / /^fW^O^ft 
 
 three feet deep in the ground, / / / ..^^draM 
 
 and one foot in from the perpen- y /(^mfilnlKBB 
 
 dicular face of this newly ex- MW^^rM^ 
 
 posed surface." Professor Put- /'^ \ W ^M 
 
 nam gives the following descrip- jy ^^KsSi 
 
 tion of his discoveries : jf ~ ffl^^\ii^ll 
 
 A short distance from Dr. j% y.^:, Jj^^^Wi 
 
 Abbott's house, and very near ^j, ' tl' |M|^t'r^| 
 
 where the Trenton gravel joins W WV^^'^yI^^ 
 
 the marine gravel, there is a deep I jM'jjJP^i'A". IQraii 
 
 gully through which flows a small L^T^^^^^iyWriyiffl 
 
 brook. In this gully the gravel- /y^\ "'"• iR^M 
 
 bank is constantly washing away, / \ jj^jiil 
 
 and presenting new surface ex- / \ • 1/ h^hhI 
 
 posures. After a heavy rain in ( r vXn " '/ ^^Mn 
 
 June, 1879, I visited the spot | ^i v M^mJIHi} 
 
 with Dr. Abbott and his son. I m tfrn^Klf 
 
 Here I noticed a small bowlder \ ^ llil rSiSw 
 
 of about six or eight inches m . \ fflll ^ IH W 
 
 diameter, projecting an inch or >y wm 1 iM w 
 
 two from the face of the bank x^_^ J? Hi ^ M^ 
 
 about four feet from the surface ^^'w^jjl^*!''^ 
 
 of the soil above ; I worked the Pm. leo.— side view of the preceding. 
 
 stone from the gravel in which " "*™' 
 
 it was firmly imbedded and drew it out. At the back part of 
 
 the cavity thus made I noticed the pointed end of a stone, and 
 
 * " Proceedings of the Boston Society of Natural History," vol. xxi, p. ' 45 
 
628 
 
 THE IGE AQE IN NORTH AMERICA. 
 
 after w;orking it up and down a few times, so as to loosen the 
 gravel about it, I drew out the implement now exhibited. 
 
 Fig. 161.— Argillite implement found by Dr. C. C. Abbott, MaTCh, 1879, at A. K. Bowan's 
 farm, Trenton, New Jersey, in gravel sizteen feet from surface, a, face view ; by 
 side view. (No. 11,286.) (Putnam.) 
 
 On the same day I discovered a second specimen in place 
 eight feet from the surface, and Dr. Abbott's son Richard 
 found another about four f^et from the surface. These three 
 specimens were found within twenty or thirty feet of each 
 other, after a heavy shower had made the most favorable con- 
 ditions for their discovery. 
 
 My own first visit to the locality was in November, 1880, 
 in company with Professors W. Boyd Dawkins, Henry W. 
 Haynes, and H. Carvill Lewis, when we were conducted by 
 Dr. Abbott to the various localities favorable for investiga- 
 tion. Professor Lewis and myself also repeatedly visited the 
 
MAN AND THE OLACIAL PERIOD. 
 
 629 
 
 locality afterward. But neither of us was ever so fortunate 
 as to find a palaeolithic implement in place, or even in the 
 fresh talus of the blufE facing the river. As our experience 
 is that of many others who have visited the locality, and 
 hence of attempts in some quarters to throw doubts upon the 
 genuineness of Dr. Abbott's' discoveries, it is worth while to 
 record that Professors Dawbins and Haynes independently 
 
 Fig. 162.— Chipped pebble— black chert, fonnd by Dr. C. C. Abbott, 1876, near the site 
 of Latheran church, Trenton, New Jersey, in gravel six feet below the surface, a, 
 face view ; 6, side view. (No. 10,986.) (Putnam.) 
 
 found implements in the talus over which we had passed a 
 moment or two before ; but, as the attention of Professor 
 Lewis and myself was directed chiefly to the geological prob- 
 lems relating to the character and age of the deposit itself, 
 our failure to discover implements where trained eyes saw 
 them but illustrates the limitations of observers. To distin- 
 gmsh a roughly flaked human implement in a bed of gravel 
 and pebbles where the ratio of artificial flakes to the natural 
 forms is as one to a million, is like finding a needle in a hay- 
 mow. Hence negative evidence, or a failure of particular 
 
630 THE ICE AGE IN NORTH AMERICA. 
 
 observers to find implements, has very little weight in 
 discrediting the testimony of others who have been more 
 successful. 
 
 The acrimonious controversy over the genuineness of 
 these implements of supposed glacial age was finally put to 
 rest by a fortunate discovery made by Mr. Ernest Volk, while 
 working under the auspices of the Peabody Museum of Cam- 
 bridge, Mass. The discovery was that of a human femur, in 
 undisturbed gravel twenty feet below the surface, and be- 
 neath a thick deposit of crossbedded coarse gravel which 
 unquestionably belongs to the glacial era. The accompanying 
 illustration of the gravel pit in which this was found lies in 
 the same bank shown in the illustration on p. 521, but after 
 the gravel bank had been excavated 100 feet or more farther 
 back from the river. 
 
 Accepting as now beyond question that these palaeolithic 
 implements at Trenton occur in undisturbed strata of the 
 gravel, of which the evidence just given would seem to be 
 sufficient, the question of the archaeologist as to the age of 
 the deposit is asked of the geologist, and it is for him to 
 answer. In the light of the preceding chapters, a ready an- 
 swer is found to this question. The city of Trenton is built 
 upon a horseshoe-shaped gravel-deposit which is about three 
 miles in diameter, extending back about that distance to the 
 east from the present river. This deposit is somewhat lower 
 around its inland boundary than along the river. The prongs 
 of this horseshoe rest, one at Trenton, and the other two 
 miles below, just north of the house of Dr. Abbott. This 
 gravel is thus described by Professor Shaler : 
 
 The general structure of the mass is neither that of ordi- 
 nary bowlder-clay nor of stratified gravels, such as are formed 
 by the complete rearrangement by water of the elements of 
 simple drift-deposits. It is made up of bowlders, pebbles, and 
 sand, varying in size from masses containing one hundred 
 cubic feet or more to the finest sand of the ordinary sea-beach- 
 
MAN AND THE GLACIAL PERIOD. 
 
 631 
 
 Fig. 1I>3. — Typical section of the Trenton eravel in which the imiolements described in 
 the text are found. Note the distinct stratification and the large angular bowlder 
 near the surface, showing the presence of floating ice, since by no other means 
 couldsuch a bowlder get into sucha position as here found. The elevation of the 
 surface is here 50 feet and is about half a mile back from the river edge of the bluff. 
 Perpendicular exposure Is here between 30 and 40 feet. 
 
 (Photograph by Abbott.) 
 
 es. There is little trace of true clay in the deposit ; there is 
 rarely enough to give the least trace of cementation to the 
 masses. The various elements are rather confusedly arranged ; 
 the large bowlders not being grouped on any particular level, 
 and their major axes not always distinctly coinciding with the 
 horizon. All the pebbles and bowlders, so far as observed, are 
 smooth and water-worn, a careful search having failed to show 
 evidence of distinct glacial scratching or polishing on their 
 surfaces. The type of pebble is the subovate or discoidal, 
 and though many depart from this form, yet nearly all ob- 
 served by me had been worn so as to show that their shape 
 had been determined by running water. The materials com- 
 prising the deposit are very varied, but all I observed could 
 apparently with reason be supposed to have come from the 
 
Fio lf,l— r.ravcldepdslt at Trenton. N. J.. whiTi' Mr. Volkfniinilii liumnn femur In Dor- 
 enilicr, 1K!I9. Tlie arrow p"lnts to the spot where the femur was discovered. 
 (CourlW-y of Ee< f.rds of t lie Past. 1 
 
Af^AT AND THE GLACIAL PERIOD. 633 
 
 extensive valley ot the river near whioh they lie, except per- 
 haps: the fragments of some rather rare hypogene rocks.* 
 
 It is now settled that the rocks from wliich these beds 
 were derived are all in place in the upper Delaware VaUey.f 
 
 The distinction between the river-gravel and that which 
 overlies the larger part of southern New Jersey is marked in 
 several ways. The Trenton gravel is much coarser than the 
 general deposit, it is also largely composed of fresher looking 
 and softei pebbles, showing that it has been subject to much 
 less abrasion than the other, and that it is of more recent 
 age ; it is also limited to the river-valley, and finally is not 
 overlaid by the Philadelphia brick-clay which, so far as it 
 extends, rests nnconformably upon the general deposit of 
 gravel. The general deposit of gravel in this region is com- 
 posed almost exclusively of small, well-rounded pebbles of 
 quartz and of hard limestone which " are not fresh looking, 
 but are eaten and weather-worn by age." 
 a bob 
 
 Via. 128.— Section across the Delaware Eiver at Trenton, New Jersey, a, a, Philadelphia 
 red gravel and brick clay (McGee^s Colnmbia deposit) : 6, 6, Trenton gravel, in which 
 the implements are found ; c, present iiood-plain of the Delaware River. (After 
 Lewis.) (In Abbott^a " Primitive Industry.") 
 
 The elevation of this implement-bearing gravel at Tren- 
 ton is not far from forty feet above the present high-water 
 limit ; and Trenton is now at the head of tide-water. These 
 gravels are continuous as a terrace all along up the river. As 
 one ascends the river, howevei-, their height (at least below 
 the Water-Gap) is reduced to fifteen or twenty feet above 
 the present flood-plain. 
 
 But most significant of all the facts indicated are the 
 character and position of the Philadelphia red gravel and 
 brick-clay. This also is confined to the river-valley and its 
 tributaries, and rests unconformably upon the older gravel 
 
 * "Report of Peabody Museum," vol. ii, 1876-79, pp. 44-47. 
 t "New Jersey Report for 1877," p. 21; Lewis on "The Trenton 
 Gravel," p. 5. 
 
634 TEE ICE AGE IN NORTH AMERICA. 
 
 formations, rising to a height of one hundred and fifty feet 
 above the river, and there ceasing. This elevation relative 
 to the river is maintained as far up as Easton, where the 
 bed of the river itself is one hundred and fifty-seven feet 
 above tide-level. Finally, the Philadelphia brick-clay con- 
 tains numerous bowlders of considerable size, derived from 
 the ledges of Medina sandstone and other rocks above. This 
 marks it as a deposit of the glacial flood some time during the 
 declining centuries of the great Ice age. 
 
 The succession of events would seem to be as follows : 
 Buriiig the early part of the Glacial period the ice accumu- 
 lated in the upper portion of the valley of the Delaware to a 
 depth of many hundred feet. The area in the valley of the 
 Delaware covered by the ice is not far from six thousand 
 square miles. It is not improbable that the average depth 
 of the ice accumulated over the region was considerably more 
 than fifteen hundred feet, or a quarter of a mile, making 
 the total accumulation of ice more than fifteen hundred 
 cubic miles, with its southern border sixty miles above 
 Trenton. All this as it melted nmst find its outlet to the 
 sea through the Delaware River. It is evident at a glance 
 that during the decline of the Glacial period, when the pro- 
 cess of melting was proceeding with greatest rapidity, the 
 floods in the valley below must have been upon a scale of 
 surprising magnitude. 
 
 And yet it is impossible that these glacial floods in the 
 Delaware should have been so enormous as to have filled the 
 valley below Trenton to the height of one hundred and fifty 
 feet, for this valley is nowhere less than five miles in width 
 and constantly enlarges toward the sea. If the water at 
 Trenton were raised one hundred and fifty feet, the slope to 
 the bay would be about two feet per mile. Now, a current 
 of five miles per hour, one hundred and fifty feet deep and 
 one naile wide, would discharge a cubic mile of water every 
 eight hours, or three cubic miles per day. (The mean rate 
 of the Ohio River, with an average descent of five inches to 
 the mile, is three miles per hour — ^that of the Mississippi 
 
MAN AND THE GLACIAL PERIOD. 635 
 
 very nearly the same.) To supply such a volume of water 
 as this, the whole accumulation of ice in the upper Delaware 
 would suffice for only five hundred days, or for about sixteen 
 months. And to furnish this amount of water there would 
 need to be, during such floods, a daily accumulation by rains 
 and the melting ice over the whole upper valley of the Dela- 
 ware of about three feet of water, which of course is incred- 
 ible, even if we suppose the floods confined to a single month 
 of each successive year. Hence, without doubt, we may con- 
 clude that the deposition of the bowlder-bearing brick-clay 
 in the Delaware Valley below Trenton implies a depression 
 of that region to the extent of one hundred or more feet. 
 
 Doubtless the region north of Trenton shared in this de- 
 pression, but, being above the tide- water, the. effects would 
 not be equally evident. The valley above Trenton is narrow ; 
 at Lambertville, about twelve miles up the stream, a trap- 
 dike contracts the valley to a width of about one quarter 
 of a mile. Above this point the supposition of floods suffi- 
 cient to deposit the bowlder-bearing clay is, therefore, not in- 
 credible, especially since the descent in the stream was prob- 
 ably less then than now. For the depression of that period 
 proceeded, as we have seen, at increased rate northward. 
 In Montreal, it was five hundred feet ; in Vermont, about 
 three hundred feet ; and how much more or less in the 
 vicinity of Lake Erie we can not tell. Such depression 
 would greatly diminish the velocity of the torrent, and the 
 narrow places in the valley would work to the same end. 
 Professor Dana has shown that in the lower part of the val- 
 ley of the Connecticut River the floods rose during the Cham- 
 plain epoch from one hundred and fifty to two hundred feet 
 above the present high-watermark. But the Connecticut 
 River Valley below Middletown is contracted by trap-dikes 
 much as the Delaware is at Lambertville ; and the drain- 
 age basin of the Connecticut is three times as extensive as 
 that of the Delaware (being twenty thousand square miles). 
 The effect of this obstruction, however, is paitly offset by 
 the branch currents which,, as Professor Dana showfi> set 
 off from the Connecticut at various places above Middle- 
 town. 
 
636 THE ICE AGE IN NORTH AMERICA. 
 
 After an exhaustive examination carried on for several 
 years in connection with the New Jersey Geological Survey, 
 Professor Salisbury reports finding deposits in that state 
 corresponding to those here spoken of as Philadelphia brick 
 clay and red gravel, which he describes under the local names 
 of Bridgeton and Pensauken, reaching a height of 200 feet 
 in the case of the former and 150 of the latter. But he is 
 inclined to refer these "in large part to subaerial (fluvial 
 and pluvial origin"). On this theory the deposits were 
 chiefly brought into place by the Delaware and its tributaries 
 during the close of the first glacial period, when the land was 
 nearly at its present level, and the streams were overloaded 
 •with glacial debris. This accumulated as abroad delta over 
 lowlands which were subsequently so much eroded that only 
 the present remnants are left. 
 
 But the extent over which the deposit is spread, as well 
 as its character militates strongly against this theory. For 
 the deposit extends for many miles northeast of the Delaware 
 at Trenton, above where the imaided current of the glacial 
 stream would carry the material, while several miles south- 
 east of Trenton, bowlders, three and four feet in diameter, 
 are found at an elevation of 200 feet, the bowlders being 
 identical in material with others bearing glacial scratches 
 found in the valley of the Delaware, twenty or thirty miles above 
 Trenton. It hardly is possible that the whole area south of 
 Trenton to the limit of these bowlders was covered with 
 Bridgeton gravel to this height. Besides, the distribution 
 of the bowlders in the brick clays of Philadelphia was evidently 
 by stranded icebergs. In this clay bowlders two and three 
 feet in diameter are distributed in a manner that would be 
 impossible in any other way. A depression of 200 feet in the 
 lower valley of the Delaware, therefore, cannot easily be 
 dispensed with. Similar facts lead to the same conclusion 
 respecting the depression at the mouth of the Susquehanna 
 at the head of Chesapeake Bay, near Havre de Grace. 
 
MAN AND THE GLACIAL PERIOD. 637 
 
 At any rate, in the Delaware Valley we find bowlder-bear- 
 ing clay rising to a height of one hundred and fifty or more 
 feet above the present high-water level. In the Lehigh 
 Valley, at Bethlehem, a few miles above its junction with 
 the Delaware, and several miles south of the limit of the ice- 
 field, Professor Lewis and myself found this bowlder-bearing 
 clay containing scratched pebbles and lying unconformably 
 upon thick deposits of coarse stratified gravel at a height 
 of one hundred and eighty feet above the river. Farther 
 up the Lehigh Valley also, near Weissport, we ascertained 
 the limit of ice-carried bowlders to be one hundred and 
 eighty feet above the river. 
 
 "We are probably safe in assuming that these floods, de 
 positing clay and bowlders at the height above mentioned, 
 mark both the period of greatest depression during the Gla^ 
 cial epoch and that when the ice was most rapidly melting 
 away. Of course, the deposition of what Professor Lewis 
 styles " red gravel," and the high gravels at Bethlehem, oc- 
 curred earlier, since the clay overlies them. 
 
 It is evident that the deposition of this bowlder-bearing 
 clay is separated from that of the implement bearing gravel 
 at Trenton by a period of considerable physical changes, if 
 not of vast time. 
 
 Considering, now, this Trenton gravel, we find it to be 
 limited at the head of tide-water to a level of about forty 
 feet, and diminishing in height relatively to the river both 
 as one ascends and aB one descends the channel, until at 
 Yardleyville, a few miles above Trenton, it merges into the 
 terrace which maintains a pretty uniform height of fifteen or 
 twenty feet above the river all the way to the Water-Gap. 
 Above the Water-Gap the gravel terraces rise t6 a much 
 greater height. At Stroudsburg a second terrace stands 
 seventy-five feet above the first terrace, which is about fifteen 
 feet above Broadhead Creek. But this upper terrace is 
 kame-like in its structure, and hence would be explained in 
 part by the lingering presence of the glacier itself. 
 
 The descent of the river-valley from Belvidere, where the 
 
638 THE ICE AGE IN NORTH AMERICA. 
 
 ice-sheet terminated, to Trenton, is two hundred and thirty- 
 two feet, or at the rate of nearly four feet per mile. 
 
 Now, the transportation of gravel by a river is dependent 
 both upon the amount of material accessible to the running 
 stream and upon the rapidity of the current. Toward the 
 close of the Glacial period the pebbles accessible to the stream 
 were superabundant, having been deposited in excessive 
 amount by the melting of the glacier in the lower latitudes. 
 The water-worn pebbles at Trenton were probably largely 
 derived from this source. Even a glacial torrent may have 
 more loose material than it can manage, and so may silt up 
 its bed with gravel. Hence it is not necessary to suppose 
 the river at this point to have been of sufficient volume to 
 fill the whole valley with water to the height of the terraces, 
 fifteen or twenty feet. The river may have flowed upon a 
 more elevated gravel bottom in a shallower current than the 
 terrace would seem to imply. 
 
 When, now, the current, passing down this declivity of 
 four feet to the mile, reached the level of the sea at Trenton, 
 its transporting power would be greatly diminished, and thus 
 we should have an accumulation of gravel at the head of 
 tide-water, without bringing into the problem the supposition 
 of any very extraordinary increase in the volume of the 
 river. The transporting capacity of a stream of water is esti- 
 mated to vary as the sixth power of the velocity ; i. e., if a 
 current is checked so that it moves at only half its former 
 rate, its transporting capacity is diminished to one sixty- 
 fourth.* It is easy to see that the sudden enlargement of 
 the valley just above Trenton, as well as the occurrence there 
 of tide-water, would diminish the rapidity of the river, and 
 hence cause an extraordinary deposition of gravel when 
 the moraines above were fresh and when ice-fields still lin- 
 gered in the southern valleys of the Catskills. The process 
 of deposition must have been so rapid that it might well 
 have taken place not long before the withdrawal of the con- 
 
 *See Le Conte's " Elements of Geology," pp. 18-20. 
 
MAN AND THE GLACIAL PERIOD. 639 
 
 tinentaJ glacier to the north of the Catskills. The time re- 
 quired for the river under present conditions to erode the 
 channel it now occupies was of much greater duration. The 
 following is the probable course of events : 
 
 1. The Philadelphia brick-clay was deposited during the 
 height of the Glacial epoch, when the Delaware Valley was 
 considerably depressed below its present level. This is Mc- 
 Gee's Columbia period. 
 
 2. Toward the close of that period, when the land bad 
 resumed its present level and the ice had nearly all dis- 
 appeared south of the Catskills, the still swollen stream 
 brought down the superabundant loose material from the 
 kames and moraines of the glaciated area and deposited it in 
 the valley below. The material was so abundant that doubt- 
 less the whole channel was silted up so that the bed of the 
 river was considerably above that it now occupies. At Tren- 
 ton it flowed over and through an extensive delta of coarse 
 graivel forty feet above its present level ; and, above Trenton, 
 over ian accumulation of gravel from fifteen to twenty feet 
 above the present high-water mark. This period was marked 
 by the presence of the mastodon and other extinct animals 
 with palaeolithic man in the neighborhood of Trenton.* 
 
 3. During the Terrace epoch the river worked its way 
 down through the delta gravel at Trenton, and has since 
 eroded its present channel which is about two miles wide at 
 that point. Higher up, where the current is swift, the lateral 
 erosion in recent times has been small. 
 
 4. '• To determine approximately the date of the earliest 
 evidence of man's appearance at Trenton we have as data : 
 (1) The amount of erosion in the gravel at Trenton. (2) The 
 
 * It should have been mentioned earlier that Professor Cook found in this 
 gravel, fourteen feet below the surface, the tusk of a mastodon, and that near 
 the same place, at a depth of sixteen feet from the surface. Dr. Abbott took 
 from it a portion of a human under-jaw, also from another place a human tooth, 
 and from still another - " very thick and in several respects singular human 
 cranium." Interesting as these are, however, they are too fragmentary to add 
 materially to our information derived from the implements. See " Annual Geo- 
 logical Report for New Jersey for 1878," p. 24; "Report of Peabody Museum 
 for 1886," p. 408. 
 
640 THE 10 E AGE IN NORTH AMERICA. . 
 
 general evidence from other sources bearing upon the date 
 of the close of the Glacial epoch in this country, more fully 
 treated of in the preceding chapter. 
 
 Since my first visit to Trenton I have studied attentively 
 all the streams situated like the Delaware with reference to 
 the glaciated area between the Atlantic Ocean and the Mis- 
 sissippi Kiver, and can state from personal observation, as 
 heretofore detailed, that a common cause, which can not be 
 anything else than glacial floods operating while the ice re- 
 mained over the head-waters of these streams, has been at 
 work tilling them with gravel-deposits similar to those de- 
 scribed along the Delaware. Without exception, those south- 
 erly-flowing streams, whose drainage area lies to any consider- 
 able extent within the glaciated regions, are lined by exten- 
 sive terraces of the overwash gravel of the Glacial period. 
 
 On obtaining definite information as to these facts, 1 at 
 once pointed out * the importance of having local observers 
 turn their attention to the discovery of palaeoliths at various 
 points in Ohio, where the glacial conditions were similar to 
 those in the valley of the Delaware at Trenton. In my re- 
 port to the Western Reserve Historical Society (p. 26) I wrote 
 as follows: "The gravel in which they [Dr. Abbott's im- 
 plements] are found is glacial gravel deposited upon the 
 banks of the Delaware when, during the last stages of the 
 Glacial period, the river was swollen with vast floods of 
 water from the melting ice. Man was on this continent at 
 that period when the climate and ice of Greenland extended 
 to the mouth of New York Harbor. The probability is, that 
 if he was in New Jersey at that time, he was also upon the 
 banks of the Ohio, and the extensive terrace and gravel de- 
 posits in the southern part of our State should be closely 
 scanned by archaeologists. When observers become familial 
 with the rude form of these palaeolithic implements, they will 
 
 * " American Journal of Science," vol. cxxvi, pp. 7-14 ; " The Glacial 
 Boundary in Ohio, Indiana, and Kentucky " ; " Western Reserve Historical 
 Society," 1884, pp. 26, 27 ; " Ohio Archaeological and Historical Quarterly," 
 vol. i, pp. 176, 177. 
 
MAlf AND THE GLACIAL PERIOD. 641 
 
 doubtless find them in abundance. But whether we find 
 them or not in this State [Ohio], if you admit, as I am com- 
 pelled to do, the genuineness of those found by Dr. Abbott, 
 our investigation into the glacial phenomena of Ohio must 
 have an important archaeological significance, for they bear 
 upon the question of the chronology of the Glacial period, 
 and so upon that of man's appearance in ISTew Jersey." 
 
 The substance of these remarks had been previously made 
 by me in a meeting of the " Boston Society of Natural His- 
 tory " for March 7, 1883, and reported in " Science," vol. i, pp. 
 269-271. Commenting upon this report Dr. Abbott sent a 
 communication to " Science," from which the following ex- 
 tracts are very significant and interesting as connected with 
 the discussion : 
 
 In "Science" of April 13th, p. 371, Professor Wright re- 
 marks that " no palaeolithic implements have yet been found 
 [in Ohio], but they may be confidently looked for." It has 
 seemed to me possible, from my own studies of the remains of 
 palaeolithic man in the valley of the Delaware Eiver, that traces 
 of his presence may only be found in those river-valleys which 
 lead directly to the Atlantic coast, and that palaeolithic man 
 was essentially a coast-ranger, and not a dweller in the interior 
 of the continent. If we associate these early people with the 
 seal and walrus rather than with the reindeer, and consider 
 them essentially hunters of these amphibious mammals rather 
 than of the latter, it is not incredible, I submit, that they did 
 not wander so far inland as Ohio, nor even so far as the east- 
 ern slope of the Alleghanies ; and we need not be surprised if 
 palaeolithic implements, concerning which there can be no 
 doubt whatever — for recent Indians made and used stone imple- 
 ments that are "palaeolithic" in character — are not found in 
 Ohio, nor even in Pennsylvania west of the valley of the Sus- 
 quehanna River. . . . 
 
 On the other hand, if the relationship of palaeolithic man 
 and the Eskimo is not problematical, and the latter is of Ameri- 
 can origin, then I submit that man was preglacial in America, 
 was driven southward by the extension of the ice-sheet, and 
 probably voluntarily retreated with it to more northern re- 
 
642 
 
 TEE ICE AGE IR NORTH AMERICA. 
 
 gions ; and, if so, then in Ohio true palseolithic implements will 
 surely be found, and evidences of man's preglacial age will ulti- 
 mately be found in the once-glaciated areas of our continent.* 
 
 The expectation of finding evidence of preglacial man 
 in Ohio was met not long after this. 
 
 At a meeting of the Boston Society of Natural History f 
 for November 4, 1885, " Mr. Putnam showed an implement 
 chipped from a pebble of black flint, found by Dr. C. L. 
 
 Fig. 166. -Chipped pebble of black chert, found by Dr. C. L. Metz, October, 1885, at Madi- 
 sonville, Ohio, in gravel eight feet from surface under clay, a, face view ; 6,- side 
 view. Note its resemblance to Fig. 136, from Trenton, New Jersey. (No. 40,970.) 
 (Putnam.) 
 
 Metz, in gravel, eight feet below the surface, in Madison- 
 ville, Ohio. This rude implement is about the same size and 
 shape of one made of the same material, found by Dr. Ab- 
 bott in the Trenton (N". J.) gravel, and is of special interest 
 as the first one known from the gravels of Ohio." Professor 
 Putnam's announcement, followed by a letter from Dr. Metz, 
 saying that he had since found another implement in the 
 
 * "Science," vol. i, p. 359. 
 
 ■j- " Proceedings," vol. xxiii, p. 242. 
 
MAN AND THE OLAGIAL PERIOD. 
 
 643 
 
 gravel at Loveland, led me, on the 11th and 12th of No- 
 vember, 1887, to visit the localities and see their relation to 
 the glacial deposits of the region. The situation is as fol- 
 lows : 
 
 Fig. 167. — Map showing glacial boundary, ctiannels, and terraces near Cincinnati, 
 
 Madisonville is situated eleven miles northeast of Cincin- 
 nati, in a singular depression, connecting the Little Miami 
 River with Mill Creek, about five miles back from the Ohio 
 (see Fig. 167). The Little Miami joins the Ohio some miles 
 above Cincinnati, while Mill Creek joins it just below the 
 
644 THE ICE AGE IN NORTH AMERICA. 
 
 city. The general height of the hills in that vicinity above 
 the river is from four hundred to five hundred feet. But 
 tlie hills just north of Cincinnati are separated from the 
 general elevation farther back by the depression referred to, 
 in which Madisonville is situated. 
 
 The depression is from one to two miles wide, and about 
 live miles long, from one stream to the other, and is occu- 
 pied by a deposit of gravel, sand, and loam, clearly enough 
 belonging to the Glacial-terrace epoch. Recent investigations 
 make it probable that the Ohio formerly flowed north through 
 Mill Creek, and joiaed the Great Miami near Hamilton. The 
 surface of this is generally level, and is about two hundred 
 feet above the low- water mark in the Ohio. On the east 
 side, on the Little Miami River, at Red Bank, opposite Madi- 
 sonville, the gravel is coarse, merging into pebbles from one 
 to three or four inches through, interstratified with sand, and 
 underlaid, near the river-level, with fine clay. There is here 
 a thin covering of loess, or fine loam. On going westward 
 this loess-deposit increases in thickness, being at Madison- 
 vUle, one mile west, about eight feet thick. Farther west 
 it is much deeper, and seems to take the place of the gravel 
 entirely. At several railroad cuttings, compact glacial clay 
 appears underneath all. 
 
 Thus, it is evident that this cross-valley, connecting Mill 
 Creek with the Little Miami back of Avondale, Walnut 
 Hills and the observatory, was once much deeper than now, 
 and has been filled in with deposits made when immense 
 glacial floods were pouring down these two streams from the 
 north. The Little Miami was a very important line of glacial 
 drainage, as is shown by the extensive gravel-terraces all along 
 its course, to which the railroads resort for ballast. The 
 coarser material was deposited near the direct line of drainage, 
 where the current was strong, while back from the river to- 
 ward Madisonville, there was naturally an increase of the fine 
 deposit, or loess, which is practically a still-water formation. 
 
 Li making an excavation for a cistern, Dr. Metz pene- 
 trated the loess, just described, eight feet before reaching 
 
MAN AND THE GLACIAL PERIOD. 645 
 
 the gravel, and there, just below the surface of the gravel, 
 the implement referred to was found. There is no chance 
 for it to have been covered by any slide, for the plain is ex- 
 tensive and level-topped, and, according to Dr. Metz, there 
 had evidently been no previous disturbance of the gravel. 
 
 Subsequently, in the spring of 1887, Dr. Metz found 
 another palseolith in an excavation in a similar deposit in the 
 northeast corner of the county, on the Little Miami across 
 from Loveland. The river makes something of an elbow 
 here, open to the west. This space is occupied by a gravel- 
 terrace about fifty feet above the stream. The terrace is 
 composed in places of very coarse material, much resembling 
 that of Trenton, N. J., where' Dr. Abbott has found imple- 
 ments. The excavation is about one quarter of a mile back 
 from the river, near the residence of Judge Johnson. The 
 section shows much coarser material near the surface than at 
 the bottom. The material is largely of the limestones of the 
 region, with perhaps ten per cent of granitic pebbles. The 
 limestone pebbles are partially rounded, but are mostly ob- 
 long. Some of them are from one to three feet in length. 
 These abound for the upper twenty feet of the section on 
 the east side toward the river. One granitic bowlder noticed 
 was about two feet in diameter. On the west side of the 
 cut, away from the river, mastodon-bones were found in a 
 deposit of sand underlying the coarser gravel and pebbles. 
 It was here, about thirty feet below the surface, that Dr. 
 Metz found the palaeolithic implement referred to. 
 
 In October, 1889, Mr. W. C. Mills, president of a local 
 archaeological society of some importance at Newcomerstowu, 
 on the Tuscarawas Eiver, in Ohio (see map on page 168), found 
 a flint implement of palaeolithic type fifteen feet below the sur- 
 face of the glacial terrace bordering the valley at that place. 
 The facts were noted by Mr. Mills in his memorandum-book at 
 the time, and the implement was placed with others in his col- 
 lection. But, as he was not familiar with implements of that 
 type, and did not at the time know the significance of these 
 gravel deposits, nothing was said about it until meeting me the 
 following spring, when I was led from liis account to suspect 
 
646 
 
 THE ICE AGE IN NORTH AMERICA. 
 
 the importance of the discovery. Mr. Mills soon after 
 sent the implement to me for examination, and its value 
 at once became apparent. In companj' with Judge C. C. 
 Baldwin and two or three other prominent citizens of 
 Cleveland, I inunediateh' visited Newcomerstown. A cut 
 
 
 ^ 
 
 
 
 
 
 Plii. 168. — Tlic smjilli'C is tlie paljiMilitli from Newroinrrstown. tlu' liirirer from Amiens 
 
 (face vii'wl. 
 
 of the implement is given in the accompanying pages, 
 made from a photograph one quarter the diameter. Beside 
 it is a palceolith which came into my possession from Dr. 
 Evan's collection in London, with his certification that it 
 is from the valley of the Somme. The two implements as 
 tlicy ai)])(';ir side l)y side, are in shajie and finish the exact 
 
MAN AND THE GLACIAL PERIOD. 
 
 64^ 
 
 counterparts of each other. The one from Newcomers- 
 iovm, however, is made from a local flint which occurs in 
 nodules in the "Lower Mercer" limestone, which is situated 
 in the lower part of the coal-measures, and crops out a few 
 miles from there. 
 
 Fir.. 169.- Rrl!;i- view nf tlif pivcert iii^'. 
 
 The implement has upon it tlie jxitina characteristic of 
 the genuine flint implements of groat age in the valley of 
 the Somme, and is recognized by Professor Haynes, of 
 Boston, as in itself fuUfilling all the requirements looked 
 for in such a discovery. The gravel-pit in which it was 
 found is one which for some j'cars has l)ecn resorted to hv 
 
648 
 
 THE ICE AGE IN NORTH AMERICA. 
 
 the railroads for ballast. Mr. Mills saw the implement as 
 it was projecting from the undisturbed gravel in the fresh 
 exposure, and took it out with his own hands. The surface 
 of the glacial terrace is here thirty-five feet above the 
 prefent high-water mark of the river, and, as already said, 
 the implement was found fifteen feet below the surface. 
 The terrace is one which characterizes the Tuscarawas 
 River everjTvhere below the glacial boundary, and the 
 illustration upon page 324 might well have been taken 
 from this very spot. 
 
 Fig. 170— Face View 
 of the Implement 
 
 Fig. 171 — Face View. 
 
 Fig. 172— Diagonal View 
 of Sharpened Edge. 
 
 In 1892 another important discovery was made in the upper 
 terrace of the Ohio River at Brilliant, Ohio. This was a well 
 fashioned flint implement one inch long which was found in 
 place beneath eight feet of cross bedded sand and gravel where 
 there had been no chance for secondary deposition or a land 
 slip. The surface of the terrace was nearly uniform for two 
 miles in length and a quarter of a mile in -width at a height 
 of 80 feet above low water, and fifty feet above the present 
 high water mark. Excavations near by to a depth of 43 feet 
 show continuous cross bedded stratification of sand and gravel 
 with clay in small quantities. Mr. Sam Huston, the County 
 Surveyor, and a well known geological collector of highest 
 
MAN AND THE GLACIAL PERIOD. 
 
 649 
 
 reputation saw the point of the implement projecting from 
 the perpendicular bank while the workmen were at dinner, 
 and extracted it with his own hands. The implement was 
 submitted to the joint meeting of the Geological and Anthro- 
 pological sections of the American Association for the Ad- 
 vancement of Science at Springfield Mass., in 1895, where 
 Professor F. W. Putnam, Mr. F. H. Gushing and Miss AUce 
 Fletcher and others all recognized it as an indubitable rehc 
 of great antiquity. 
 
 Its great age was indicated by the patina with which it 
 was covered, and by the fact, instantly recognized by Dr. 
 Gushing, that the form was antique, being intermediate 
 between that of paleoliths and modern Indian implements. 
 
 Fig. 173.— Section of the Trough of the Ohio at Brilliant, 
 the Implement shown by a *. 
 
 Location of 
 
 For full accounts see "Popular Science Monthly" for De- 
 cember 1895, pp. 157-166. 
 
 The cumulative evidence of these facts is increased with 
 the discovery, by Mr. Hilborne T. Gresson, of Philadelphia, 
 in 1886, of implements of similar type in Medora, Ind. 
 Medora is situated in Jackson county, about one hundred 
 miles west of Gincinnati, and is on the border of the glaciated 
 region in that State. The situation is upon the East Fork of 
 White River, near where it enters the triangular unglaciated 
 portion of Southern Indiana as seen in the map of the gla- 
 cial boundary. The eastern border of this .consists of sand- 
 
Fig. 174._Palaeolith of gray flint, found by Mr. H. T. Cresson, May 1886, at Medora, In- 
 diana. In glacial gravel, eleven feet from surface, in bluff ou east fork of White Ri\ lt. 
 (Face view.) (No. 46,145.) (Putnam.) 
 
¥ 
 
 / 
 
 ' ;/ 
 
 / 
 
 ■XA 
 
 Fig. 1 7.:.— Side view of the preceding. (Putnam.') 
 
652 
 
 THE ICE AGE IN NORTH AMERICA 
 
 stone knobs formed by the outcropping of the subcarbonif- 
 erous strata, which here dip to the west. The unglaciated 
 area is, therefore, considerably higher than that which adjoins 
 it on the east, and is much cut up into gorges along 'the 
 drainage lines, and must have furnished a favorite retreat, 
 both for man and animals, during the maximum extension of 
 the ice. 
 
 Mr. Cresson, having been called into this locality on busi- 
 ness, and finding that it was near the glaeial boundary as I 
 had recently traced it, was led to tarn aside for an hour or 
 two to examine a bank of modified drift. While digging 
 with his hunter's knife under a bowlder of about one hun- 
 dred pounds weight to see if it showed signs of glaciation, he, 
 to his surprise encountered a well-wrought palasolithic flint 
 implement. Fortunately, a long experience in exploring the 
 gravel-beds in France where palaeoliths occur (and, indeed 
 from experience in exploring while a youth a shelter-cave 
 which we will hereafter describe, on the banks of the Dela- 
 ware) had prepared him fully to appreciate the discovery; 
 
 Fig. 176.— Section of erlncial gravel at Medora, Indiana, in which Mr. Cresson found the 
 palseolith fianred in the text. A. is a deooeit of soil three feet in depth ; B, modified 
 drift eight feet in depth ; D. is probably till ; L, L, layers of alluvium ; C, the bowl- 
 der, under which the implement was foiind at X. 
 
 and he remained a day or two uutil he had thoroughly in- 
 vestigated the surroundings and made further search for im- 
 plements. Such search, however, was not rewarded with suc- 
 cess, since all that he found later were from the surface, and 
 of a neolithic type. According to Mr. Cresson, this palseo- 
 
MAN AND THE GLACIAL PERIOD. 
 
 653 
 
 lith was found in undisturbed gravel about fifty feet above 
 the flood-plain of the river. The gravel was lirmly packed, 
 and the implement was with difficulty extricated from it with 
 his hunting-knife. Above it and the bowlder just mentioned 
 were eight feet of gravel and loam, capped by three feet of soil. 
 Mr. Cresson was thoroughly convinced that it vsrould have 
 been impossible for any implement of recent manufacture to 
 have rolled down from the soil above and assume the position 
 it was in with reference to the bowlder. Besides, the imple- 
 ment is of a true palaeolithic type, and has the usual marks 
 of age characterizing such implements.* 
 
 .«j^^ 
 
 2 
 
 a 
 
 Fig. 177. — 1, a, convex surface of a chert implement found at the month of Little Elk 
 River, MorriBon County, KinneBota, suppoBed to be a ecraper. 1. b. profile view of the 
 aame.t 2, a, convex Burface of a chert implement found at Little Falls. Minnepota. 
 3, b. profile view of the same. The figures do not perfectly represent the evident- 
 ly chipped edges. (Winchell.) 
 
 Another locality especially worthy of attention, in which 
 palseoliths have been found, is at Little Falls, Morrison 
 county, Minnesota, the situation of which can readilv be seen 
 by reference to tlie map on page 546. The first discover- 
 ies at this point were made as long ago as 1877, and an ac- 
 count of them was given in the " Sixth Annual Geological 
 Report of Minnesota." X These implements were made from 
 chert and quartz, and were recognized by Professor N. H. 
 
 * See Mr. Cresson's report on the subject, in the " Proceedings of the Boston 
 Society of Natural History," vol. xxiv, p. 160 e< uq. 
 
 \ This Bpecimen is regarded a finished i-nplement by Putnam. % Pp. 53-58. 
 
654 THE IGE AGE IN NORTH AMERICA. 
 
 Winchell as belonging to the age of the glacial deposits 
 which here line the trough of the Mississippi. A little later, 
 Miss Franc E. Babbitt examined the locality more carefully, 
 and found a large number of additional implements. 
 Her discoveries were first reported in a paper read before 
 the Minnesota Historical Society in February, 1880. A 
 fuller account was presented at the meeting of the Ameri- 
 can Association for the Advancement of Science at Minne- 
 apolis in August, 1883. At that time also the subject was 
 thoroughly canvassed by the numerous geologists present, 
 and a paper was read upon the subject by Mr. Warren 
 Upham, to whose work upon the surface geology of the 
 Northwest we have so often had occasion to refer. To get 
 the whole subject before our readers we can do no better 
 than to append the principal piortion of an elaborate paper 
 read by Mr. Upham before the Boston Society of Natural 
 History, on December 31, 1887, which will be the more 
 readily understood by reason of the previous chapters of the 
 present volume detailing the general results of Mr. Upham's 
 work iu that region : 
 
 The recession of the ice-sheet of the last Glacial epoch in 
 Minnesota seems to be clearly marked by as many as ten 
 stages of halt or readvance, in which distinct marginal mo- 
 raines were accumulated, besides the moraine on the limits 
 of its farthest extent. Six summers of geologic field-work 
 in that State have been spent by the writer chiefly in the 
 examination of its glacial and modified drift, of these mo- 
 raines, and of the beaches and deltas of the glacial Lake 
 Agassiz, which was formed in the valley of the Red River of 
 the North and of Lake Winnipeg by the barrier of the 
 departing ice-sheet. In their bearings upon this subject, my 
 observation and study of that region convince me that the 
 rude implements and fragments of quartz discovered at Little 
 Falls were overspread by the glacial flood-plain of the Mis- 
 sissippi River, while most of the northern half of Minnesota 
 was still covered by the ice, contemporaneously with its for- 
 mation of the massive moraines of the Leaf Hills and with 
 
MAJSr AND THE GLACIAL PERIOD. 655 
 
 the expansion of Lake Agassiz on their west side, respectively 
 sixty and eighty-five miles west of Little Palls. This was 
 during the highest stage of Lake Agassiz, and previous to its 
 extension beyond the north line of Minnesota and Dakota. 
 More than twenty lower beaches of this glacial lake have been 
 traced, belonging to later stages in the recession of the ice- 
 sheet, before it was melted so far as to reduce Lake Agassiz 
 to its present i-epresentative, Lake Winnipeg. Estimated by 
 comparison with the series of moraines and beaches formed 
 during the glacial recession, the date of the gravel plain at 
 Little Falls appears to be about midway between the time of 
 maximum extent of the last ice-sheet and the time of its 
 melting on the district across which the Nelson Eiver flows 
 to Hudson Bay. 
 
 The town of Little Falls is on the east bank of tlie Mis- 
 sissippi River, in Morrison county, near the geographic center 
 of Minnesota. It is about a hundred miles northwest from 
 St. Paul and Minneapolis, and nearly an equal distance 
 southeast from Itasca. Lake. The elevation of Itasca Lake 
 is about 1,450 feet above the sea ; of the Mississippi, at the 
 head of the rapids or Little Falls, from which the town derives 
 its name, 1,090 feet ; and at the head of St. Anthony's Falls 
 in Minneapolis, 796 feet. Following the general course of 
 the river, without regarding its minor bends, its descent from 
 Lake Itasca by Little Falls to Minneapolis averages about two 
 feet per mile, and is approximately uniform along the entire 
 distance. Considered in a broad view, this central part of the 
 State may be described as a low plateau, elevated a few hundred 
 feet above Lake Superior on the east and the Eed River Valley 
 on the west. In most portions it is only slightly undulating 
 or rolling, but these smooth tracts alternate with belts of 
 knolly and hilly drift, the recessional moraines of the ice- 
 sheet, which commonly rise fifty to one hundi'ed feet, and in 
 the Leaf Hills one hundred to three hundred and fifty feet 
 above the adjoining country. The bed-rocks are nearly every- 
 where concealed by the drift-deposits, into which the streams 
 have not eroded deep valleys, their work of this kind being 
 mostly limited to the removal of part of their glacial flood- 
 plains. The upper })ortions of the Mississippi and of its 
 
656 TEE IGE AGE IN NORTH AMERICA. 
 
 chief tributaries, and all the smaller streams throughout this 
 region, flow in many places through lakes which they have 
 not yet filled with silt nor drained by cutting down their 
 outlets. At Little Falls the glacial flood-plain of the Mis- 
 sissippi is about three miles wide, reaching two miles east, 
 and one mile west from the river. Its elevation is twenty- 
 five to thirty feet above the river at the head of the rapids, 
 which have a descent of seven feet. The Mississippi here 
 flows over an outcrop of Huronian slate, and the same forma- 
 tion is also exposed by the Little Elk Eiver near its mouth, 
 on the west side of the Mississippi three miles north of Little 
 Falls. Veins of white quartz occur in the slate at both these 
 localities, and were doubtless the source of that used by man 
 here in the Grlacial period for the manufacture of his quartz 
 implements. 
 
 The locality and section of the modified drift, where these 
 worked fragments of quartz were found by Miss Babbitt, 
 and the account of their discovery, are best told in her own 
 words from her paper read before the Anthropological Section 
 of the American Association for the Advancement of Science 
 at its Minneapolis meeting in 1883. I quote as follows : 
 
 " Eudely worked quartzes had previously been discovered 
 here by the State Geologist of Minnesota, Professor N. H. 
 Winchell, by whom they had been described and figured in 
 the State Geological Eeport for 1877. . . . The find reported 
 by Professor Winchell consists of chipped objects of a class 
 generally ascribed to what is called the rude stone age. Of 
 these many appear to be mere refuse, while others are regarded 
 as finished and unfinished implements. The Winchell speci- 
 mens have been assigned, upon geological ground, to a pre- 
 historic era antedating that of the mound-building races, and 
 reaching back to a time when the drift material of the terrace- 
 plain was just receiving its final superficial deposit. It is 
 found that, at intervals, the surface soil of the terrace con- 
 tains these quartzes to a depth of not unfrequently three or 
 four feet. 
 
 "The lowest and newest formation at this place is the 
 present flood-plain of the river. It is still in process of depo- 
 sition, being yet subject to partial overflows at periods of 
 
MAN AND THE GLAOIAL PERIOD. 
 
 657 
 
 exceptionally high water. In that portion of the town of 
 Little Falls situated east of the Mississippi, this bottom-land 
 is limited on the east by a high, ancient river-terrace, which 
 has here an average elevation of about twenty-five feet above 
 the river. . . . This older terrace, like the present flood-plain, 
 has been spread out by the immediate action of water. . . . 
 
 Fig. 178 Quartz implement, found by Miss F. E. Babbitt, 1878, at Little Falls. Minneso- 
 ta, In modified drift, fifteen feet lielow surface, o, face view ; ft, profile view. Tlie 
 black represented on the cut is the matrix of the quartz vein. (No. 31,323.) (Put- 
 nam.) 
 
 While occupied in examining the river bank at Little Falls in 
 quest of wrought quartzes, one day during the season of 1879, I 
 had occasion to ascend a slope lying between the new flood-plain 
 and the older terrace, by a path leading through a sort of gap 
 or notch in the latter (three hundred and ten rods, very nearly, 
 or almost one mile north of the east-west road by Vasaly's 
 Hotel ; ten rods west of the road to Belle Prairie ; and thirty- 
 eight rods from the river). . . . It seemed that at some past 
 period a cut had been effected here by drainage, and that the 
 wash-out thus formed had afterward been deepened by being 
 
658 
 
 THE lOE AGE IX NORTH AMERICA. 
 
 used, now and then, as a wagon-track. In this notch I dis- 
 covered the soil to be thickly strewed with pieces of sharp, 
 opaque quartz. These were common-ly of a white color, and 
 ranged in size from minute fragments to bits as large as a 
 man's hand, and in some instances even larger. There were 
 many hundreds of these chips visible, scattered over an area 
 
 Fig. 179.— Quartz implement, fomid by Miss F. E. Babbitt, 18T8, at Little Falls, Minne- 
 sota, in modified drift, fifteen feet below enrface. a, face view ; 6, side view. (No. 
 SI, 316.1 (Putnam.) 
 
 tlie width of the wagon road, and ten or fifteen yards in length. 
 They were conspicuously unwaterworn, and likewise mostly 
 unweathered, though occasionally a bit was picked up having 
 some one of its surfaces weathered, while fractured or wrought 
 faces appearing upon other parts of it, looked as fresh as if the 
 work of yesterday. On the other hand, the mass of stone 
 rubbish upon and among which the quartzes were strewed is 
 much water-worn, many of the pieces being well rounded, while 
 none of them ai-e wholly angular. 
 
 " By continued observations at tliis locality, I found that 
 many of these quartz chips were brought to light at every suc- 
 ceeding freshet of the season, being washed out of the sand by 
 
MAN AND THE GLACIAL PERIOD. 659 
 
 descending drainage. Their immense and continually increas- 
 ing numbers seemed to warrant the belief that they had re- 
 sulted from systematic operations of some sort, once conducted, 
 for unknown purposes, upon this particular spot. A portion 
 of the studied specimens subsequently yielded evidence of 
 having received shape from human hands, and therefore it 
 was assumed provisionally that the site of exposure represented 
 a prehistoric workshop. 
 
 " Prolonged investigation ensued ; and investigation estab- 
 lished the hitherto unsuspected fact that no quartz chips nor 
 fragments were inclosed in the upper part of the gravel and 
 sand terrace at the notch, nor within a considerable distance 
 at either hand, though they were sought with careful scrutiny. 
 . . . Ultimately it was ascertained that the notch quartzes had 
 dropped to the level at which they were seen from a thin layer 
 of them once lying from ten inches to two feet above it, and 
 subsequently broken up through the wearing away of the sand 
 underneath by drainage. This layer or stratum was still intact 
 on the north and south and partially so on the east, in which 
 direction it had, however, at certain points, suffered some dis- 
 placement by wagoning. It extended in a nearly horizontal 
 plane into the terrace, in the sloping edge of which the notch, 
 opening into its west bank and truncated at its edge, is cut. 
 . . . The quartz-bearing layer averaged a few inches only in 
 thickness, varying a little as the included pieces happened to 
 be of smaller or larger size. The contents were commonly 
 closely compacted, so much so that one might sometimes ex- 
 tract hundreds of fragments, many of them very small ones, 
 of course, from an area of considerably less than a square yard. 
 
 " The quartz bed, so far as examined, rested upon a few 
 inches of sandy soil, which passed downward into a coarse 
 water-worn gravel, immediately overlying till. Above the 
 quartz chips, stratified gravel and sand extended up to the sur- 
 face of the terrace. The pebbles of the gravel lying directly 
 on the quartz-bearing stratum were small and well rounded, 
 and were noticeably less angular than those of the gravel below. 
 The stratum of quartz chips lay at a level some twelve or fif- 
 teen feet lower than the plane of the terrace-top. 
 
 " These observations show that the quartz chips were spread 
 
660 THE IGE AQE IN NORTH AMERICA. 
 
 originally upon an ancient surface that has been since covered 
 deeply by the modified drift which forms the terrace. It will 
 be remembered that the quartz chips and implements discovered 
 by Professor Winehell in this ■vicinity are contained in the up- 
 per stratum of the terrace-plain ; but the notch quartzes do 
 not occur at the terrace-top, and can not have been derived 
 from it, but are confined strictly to a single stratum of the 
 lower gravels closely overlying the till. Hence the two sets of 
 objects can not be synchronous, though they may have been 
 produced by the same race at different stages of its existence. 
 The notch quartzes must, of course, be older than those de- 
 scribed by Professor Winehell, by at least the lapse of time 
 required for the deposition of the twelve or fifteen feet of modi- 
 fied drift forming the upper part of the terrace-plain, above 
 the quartz-bearing stratum." 
 
 This description by Miss Babbitt shows that these imple- 
 ments and fragments of chipped quartz occurred in a well-de- 
 fined thin layer in the modified drift forming the glacial flood- 
 plain of the Mississippi Kiver, as shown in the section which I 
 have drawn (see the following figure). I have examined the 
 
 Fro. 180.— Section across the Mississippi Valley at Little Falls, Minnesota, showing the 
 stratum in which cbipped quartz fragments were found by Miss F. E. Babbitt, as de- 
 scribed in the text. (Upham.) 
 
 terraces and plains of this valley drift from St. Paul and Min- 
 neapolis to Brainerd, some twenty-five miles north of Little 
 Falls, and find them similar in material and origin with the 
 modified drift terraces in the valleys of the Merrimack, Con- 
 necticut, and other rivers in New England. These water- 
 courses extending southward from the region that was covered 
 by the ice-sheet became the avenues of drainage from it during 
 its retreat. A part of the drift which had been contained in 
 the lower portion of the ice was then washed away by the 
 streams formed on the ice in its rapid melting and was depos- 
 ited as modified drift, forming layers of gravel, sand, and fine 
 silt, in the valleys along which the floods supplied by this 
 melting descended toward the ocean. Along the Mississippi 
 
MAX AND THE OLAGIAL PERIOD. 661 
 
 the flood-plain of modified drift at Brainerd has a height of 
 about 60 feet above the river ; at Little E'alls, as before noted, 
 its height is 25 to 30 feet ; at St. Cloud, 60 feet ; at Clear- 
 water and Monticello, 70 to 80 feet ; at Dayton, 45 feet ; and 
 at Minneapolis, 25 to 30 feet above the river at the head of 
 St. Anthony's Falls. 
 
 The modified drift at Little Falls lies on the till or direct 
 deposit of the ice-sheet, and forms a surface over which the 
 ice never readvanced. It lies far within the area that was ice- 
 covered in the second and latest principal epoch of glaciation, 
 and by reviewing the steps in the recession of the ice of that 
 epoch we shall be able to ascertain approximately what were 
 the outlines of its receding margin when the gravel and sand 
 plain of Little Falls was deposited, inclosing these evidences 
 of man's presence. The ice-sheet, supplying both this modi- 
 fied drift and the floods by which it was brought, still covered 
 much of the upper part of the Mississippi basin, which only 
 reaches about a hundred miles north of Little Falls ; and the 
 courses of massive morainic belts show the continuation of the 
 glacial boundary northwestward across Dakota and with less 
 clearness eastward across the Laurentian lakes. 
 
 When the latest North American ice-sheet attained its 
 greatest area, its southern portion from Lake Erie to Dakota 
 consisted of vast lobes, one of which reached from central and 
 western Minnesota south to central Iowa, This lobe in its 
 maximum extent ended near Des Moines, and its margin was 
 marked by the Altamont moraine, the first and outermost in 
 the series of eleven distinct marginal moraines of this epoch 
 which are recognizable in Minnesota. When the second or 
 Gary inoraine was formed, it terminated on the soutli at Min- 
 eral Ridge in Boone county, Iowa. At the time of the third 
 or Antelope moraine, it had farther retreated to Forest City 
 and Pilot Mound in Hancock county, Iowa. The fourth or 
 Kiester moraine was formed when the southern extremity of 
 the ice-lobe had retreated across the south line of Minnesota 
 and halted a few miles from it in Freeborn and Faribault 
 counties. The fifth or Elysian moraine, crossing southern Le 
 Sueur county, Minnesota, marks the next halting-place of the 
 ice. At the time of formation of the fifth moraine, the south 
 
662 
 
 THE ICE AGE IN NORTH AMERICA. 
 
 end of the iee-lobe had been naelted back a hundred and eighty 
 miles from its farthest extent, and its southwest side, which at 
 first rested on the crest of the Coteau des Prairies, had retired 
 thirty to fifty miles to the east side of Big Stone Lake and the 
 east part of Yellow Medicine county. During its next stage of 
 retreat this ice-lobe was melted away from the whole of Le 
 Sueur county, and its southeast extremity was withdrawn to 
 Waconia, in Carver county, where it again halted forming its 
 
 Fig. 181. — Map showing the stages of recession of the ice in Minnesota as described in 
 the text. (Upham.) 
 
 sixth or Waconia moraine. The seventh or Dovre moraine 
 marks a pause in its recession when its southeast end rested on 
 
MAN AND THE GLACIAL PERIOD. 663 
 
 Kandiyohi county. Probably nearly all of the southern half of 
 Minnesota was at this time divested of its ice-mantle, while 
 nearly all of the northern half was still ice-covered, the glacial 
 boundary across the State passing in an approximately east to 
 west course not far from Little Falls. 
 
 By its next recessions the ice-border was withdrawn to the 
 eighth or Fergus Falls moraine, and the ninth or Leaf Hills 
 moraine. These are merged together in the prominent accu- 
 mulations of the Leaf Hills, which reach in a semicircle from 
 Fergus Falls to the southeast, east, and northeast, a distance 
 of fifty miles, marking the southern limits of this ice-lobe when 
 ib terminated nearly due west of Little Falls and half-way be- 
 tween the south and north borders of Minnesota. Conspicuous 
 morainic hills a few miles east of Little Falls, and others in 
 the north part of Morrison county and along its west side, 
 seem to be correlated with the Fergus Falls moraine. Much 
 of the modified drift of the Mississippi Valley at Little Falls 
 was probably deposited when the ice-sheet terminated at these 
 hills five to fifteen miles distant on the east, north, and west. 
 Eastward from Morrison county, this moraine continues north- 
 east to the north side of Mille Lacs, thence probably through 
 the south edge of Aitkin county and the north part of Pine 
 county, and onward northeasterly to the west end of Lake 
 Superior. The Leaf Hills moraine extends from the northeast 
 part of the Leaf Hills, near the Leaf Lakes, east across northern 
 Todd county and northwestern Morrison county and then 
 north- north east by Gull, Pelican, White Fish, and Crooked 
 Lakes. Next it probably takes an eastward course, crossing 
 the Mississippi several miles north of Sandy Lake and the 
 St. Louis River near the mouth of the Cloquet, and thence 
 an east-northeast course passing not far south of the Cloquet 
 River- and reaching the north shore of Lake Superior about 
 half-way between Duluth and Pigeon Point. The upper portion 
 of the modified drift at Little Falls, probably including the 
 stratum of chipped fragments of quartz, is referable to the 
 time of the recession of the ice-sheet north from the Fergus 
 Falls moraine to the Leaf Hills moraine. At the west end of 
 the Leaf Hills and thence through a distance of fifty miles 
 northward, this stage of recession carried the ice-border 
 
664 THE ICE AGE IN NORTH AMERICA. 
 
 back only five to ten miles ; and in the main Leaf Hills, as 
 before noted, the two moraines are united. Across the Mis- 
 sissippi basin the glacial recession between them uncovered 
 an area mainly twenty to forty miles wide. The portion of 
 the ice-sheet nearest to Little Falls at the time of the Leaf 
 Hills moraine was in the vicinity of Fish-Trap Lake and Lake 
 Alexander, in northwestern Morrison county, only twenty 
 miles distant. There, as in the Leaf Hills, this moraine and 
 that of Fergus Falls come together. Ascending the Mississippi, 
 a distance of eighty miles intervened between Little Falls and 
 the ice-border at the time of the Leaf Hills moraine, which 
 extends approximately parallel with the river and ten to twenty 
 miles from it on its northwest side in passing north-northeast- 
 ward from Morrison county. 
 
 During the formation of the tenth or Itasca moraine, and 
 of the eleventh or Mesabi moraine, crossing the lake region at 
 the head of the Mississippi, the gravel and sand of the modi- 
 fied drift were probably wholly deposited north of Little Falls. 
 Later moi'aines, formed at times of halt or readvance, inter- 
 rupting the recession of the ice-sheet between northern Minne- 
 sota and Hudson Bay, have not been determined, but I believe 
 that they exist and await discovery when the glacial drift of 
 that wooded and very scantily inhabited region shall be fully 
 explored. The many beaches of Lake Agassiz, all showing an 
 ascent northward when compared with the level of the present 
 time, but with this ascent gradually decreased during the suc- 
 cessive stages of the lake, probably find their explanation in 
 the manner of retreat of the ice in Canada, interrupted there, 
 as farther south, by pauses and the formation of moraines. 
 
 Contemporaneously with the deposition of the glacial flood- 
 plain at Little Falls and the accumulation of the Leaf Hills, 
 the ice-front forming the north shore of Lake Agassiz crossed 
 the Eed River Valley between Fargo and Grand Forks, and ex- 
 tending northwesterly across northern Dakota, as shown by 
 its moraines remarkably developed along the south side of 
 Devil's Lake and onward to Turtle Mountain. Toward the 
 east, the ice-sheet at this time had receded from the south- 
 west part of Lake Superior, which was held about five hundred 
 feet higher than now and overflowed to the St. Croix and 
 
MAN AND THE GLACIAL PERIOD. 665 
 
 Mississippi Rivers by the way of the Bois Brulg River and Upper 
 St. Croix Lake. It seems nearly certain also that the ice- 
 border continued across Green Bay and the north part of Lake 
 Michigan ; and farther east I think that it probably crossed 
 southwestern Ontario and the central or northern portions of 
 New York, Vermont, New Hampshire, and Maine. The Lan- 
 rentian lakes were dammed by the retreating glacial barrier 
 and overflowed at the lowest points on their southern water- 
 shed. The time when the Little Palls stone implements and 
 fragments from their manufacture were covered by the modi- 
 fied drift seems therefore somewhat later than that of the im- 
 plements found in southern Ohio and in New Jersey ; for, if 
 this was the course of the ice-boundary east from the Leaf 
 Hills of Minnesota, it had already receded beyond the region 
 where the glacial floods could be discharged by the Little 
 Miami and Delaware Rivers. 
 
 If the question be asked. How many thousand years ago was 
 this ? a reply is furnished by the computation of Professor N. 
 H. Winchell, that approximately eight thousand years have 
 elapsed during the erosion of the post-glacial gorge of the 
 Mississippi from Fort Snelling to the Falls of St. Anthony ; 
 of Dr. Andrews, that the erosion of the shores of Lake Michi- 
 gan, and the resulting accumulation of dune-sand drifted to 
 the southern end of that lake, can not have occupied more than 
 seventy-five hundred years ; of Professor Wright, that streams 
 tributary to Lake Erie have taken a similar length of time to 
 cut their valleys and the gorges below their waterfalls ; and of 
 Mr. Gilbert, that the gorge below Niagara Falls has required 
 only seven thousand years or less. These measures of time 
 carry us back to the date of the Little Falls quartz- workers, 
 when the ice-sheet of the last Glacial epoch was melting away 
 from the basins of the upper Mississippi and of the Laurentian 
 lakes. 
 
 Plants and animals doubtless followed close upon the retir- 
 ing ice-border, and men living in the region southward would 
 make journeys of exploration to that limit, but probably they 
 would not take up their abode for all the year so near to the 
 ice as Little Falls at the time of the Fergus Falls and Leaf 
 Hills moraines. It may be that the chief cause leading men 
 
666 THE ICE AGE IS XORTH AMERICA. 
 
 to occupy this locality, so soon after it was uncovered from the 
 ice, was their discovery of the quartz-veins in the slate there 
 and on the Little Elk River, affording suitable material for 
 making sharp-edged stone implements of the best quality. 
 Quartz-veins are absent or very rare and unsuited for this use 
 in all the rock-outcrops of the south half of Minnesota that 
 had become uncovered from the ice, as well as of the whole 
 Mississippi basin southward, and this was the first spot acces- 
 sible whence quartz for implement-making could be obtained. 
 While the deposition of the valley-drift at Little Falls was still 
 going forward, men resorted there, and left, as the remnants 
 of their manufacture of stone implements, multitudes of quartz 
 fragments. By the continued deposition of the modified drift, 
 lifting the river upon the surface of its glacial flood-plain, 
 these quartz-chips were deeply buried in that formation. The 
 date of this valley-drift must be that of the retreat of the ice 
 of the last Glacial epoch, from whose melting were supplied 
 both this sediment and the floods by which it was brought. 
 The glacial flood-plain, beneath whose surface the quartz frag- 
 ments occur, was deposited in the same manner as additions 
 are now made to the surface of the bottom-land ; and the 
 flooded condition of the river, by which this was done, was 
 doubtless maintained through all the warm portion of the year, 
 while the ice-sheet was being melted away upon the region of 
 its head-waters. But in spring, autumn, and winter, or, in 
 exceptional years, through much of the summer, it seems prob- 
 able that the river was confined to a channel, being of insuffi- 
 cient volume to cover its flood-plain. At such time this plain 
 was the site of human habitations and industry. After the 
 complete disappearance of the ice from the basin of the upper 
 Mississippi, the supply of both water and sediment was so 
 diminished that the river, from that time till now, has been 
 occupied more in erosion than in deposition, and has cut its 
 channel far below the level at which it then flowed, excavating 
 and carrying to the Gulf of Mexico a great part of its glacial 
 flood-plain, the remnants of which are seen as high terraces or 
 plains upon each side of the river. 
 
 The question concerning the manner in. which human 
 remains have become incorporated in the glacial gravels is 
 
668 THE ICE AGE IN NORTH AMERICA. 
 
 of considerable importance as well as interest. Many have 
 seemed to assume that they could come into position only 
 by being dropped into the water from a boat. The accompany- 
 ing illustration, however, from a photograph of Professor 
 Russell taken in front of the Malaspina Glacier, Alaska, 
 shows what was doubtless the real method. A glacial delta 
 is here seen in process of formation. In the summer time, 
 when the drainage channels were overcharged both with 
 water and debris they would build up a delta terrace near 
 their mouth. During a considerable portion of the year, 
 however, these deposits would be exposed surfaces over 
 which man could wander and hunt at his leisure. In the 
 illustration such a stream has been diverted into a forest and 
 is fast burying the trees, as is seen to have been the case in 
 front of the Muir Glacier (seefrontis plate). At Trenton, 
 New Jersey, this exposed delta terrace would have been 
 doubly attractive to man from the fact that it contained 
 many pebbles of ai-gillite from which he was accustomed to 
 manufacture his implements. 
 
OHAPTEE XXII. 
 
 MAN AND THE GLACIAL PERIOD {oontmiied). 
 
 The preceding instances all belong, without question, to 
 the later stages of the Ice age in America. Those geologists 
 who speak of two glacial periods would classify the gravels 
 at Trenton, N. J., MadisonviHe and Loveland, O., Medora, 
 Ind., and Little Falls Minn., as belonging to the later stages 
 of the second Glacial epoch — the deposits at Little Falls 
 being, as Mr. Upham has already stated, somewhat subse- 
 quent to any of the others. We come now to a still more 
 startling discovery, made by Mr. Cresson, near his summer 
 residence, on the Delaware River, at Claymont, Del. For a 
 general idea of the situation the reader is referred to the 
 map of ^ew Jersey in the general chapter upon the glaciated 
 area.* The discovery was made while an extensive excava- 
 tion was in progress connected with the building of the Balti- 
 more and Ohio Railway. It was my privilege, in November 
 1888, to examine the locality in company with Mr. Cresson, 
 and I here give the results of the observations : 
 
 The point is located about one mUe and a half west of 
 the river bank, and about one hundred and fifty feet above 
 tide-water. The ascent from the river at Claymont is by three 
 or four ■ well-marked benches. These probably are not ter- 
 races, in the strict sense of the word, but shelves marking dif- 
 ferent periods of erosion, when the land stood at these sev- 
 eral levels, but now thinly covered with old river deposits. 
 The cut where the discovery was made is well shown in our 
 
 * See p. 141. 
 

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MAN AND THE GLACIAL PERIOD. 671 
 
 accompanying illustration, reproduced from a photograph. 
 The lower part of this cut consists of decomposed schist 
 rocks in place and of deposits which are preglacial. These 
 extend in the illustration to the top of the light hand run- 
 ning through the picture. The portion above this light band 
 belongs to what was described in the preceding chapter as 
 pertaining to the formation denominated by Professor Lewis 
 the Philadelphia red gravel and brick-clay, being identical 
 with that at Philadelphia both in its composition and in its 
 stratigraphical relations, and extending continuously down 
 the river from that city (nineteen miles). By Mr. McGee this 
 would be denominated the Columbia formation, since he cor- 
 relates the deposits in the Delaware Valley with those in the 
 District of Columbia in the valley of the Potomac. The age 
 of this deposit we have already discussed,* and we need here 
 only repeat that it is without doubt a glacial formation of a 
 much earlier period than that farther up the valley at Tren- 
 ton, N. J., where Dr. Abbott made his important discoveries. 
 While that at Trenton belongs to the later stages of the Ice 
 age, this at Claymont is to be connected with the ice when 
 at its maximum extension, and when the level of the region 
 was depressed one hundred feet or more. In a preceding 
 chapter I have given my reasons for questioning the theory 
 of Mr. McGee, who would connect this deposit with a glacial 
 age previous to, and entirely distinct from, that which was 
 concerned with the deposits at Trenton, and which he would 
 make from three to ten times as remote. But, whichever view 
 upon this point prevails, whether that of two distinct glacial 
 epochs, or of one prolonged epoch with various halts in the 
 retreat of the ice, the Philadelphia red gravel and brick-clay 
 must be regarded on the least calculation as some thousands 
 of years older than the deposits at Trenton, N. J., Loveland 
 and Madisonville, O., Medora, Ind., and Little Falls, Minn. 
 
 The circumstances of the discovery are thus reported by 
 Mr. Cressou : 
 
 * See pp. 613, 635 ei seg. 
 
ISl.— "Neat-cr vi<>u 
 bank when' th 
 
 (A' tile same, with thf finder pointing to the precise place in the 
 ■ inipk-iiient was found. (From photograph by Cresson.) 
 
MAN- AND THE GLACIAL PERIOD. 673 
 
 Toward midday of July 13, 1887, while lying upon the 
 edge of the railroad cut, sketching the bowlder line, my eye 
 chanced to notice a piece of steel-gray substance strongly re- 
 lieved in the sunlight against the red-colored gravel just above 
 where it joined the lower grayish-red portion. It seemed to 
 me like argillite, and, being firmly imbedded in the gravel, was 
 decidedly interesting. Descending the steep bank as rapidly 
 as possible, the specimen was, secured. . . . Upon examining 
 my specimen, I found that it was unquestionably a chipped 
 implement. There is no doubt about its being firmly imbed- 
 ded in the gravel, for the delay I made in extricating it with 
 my pocket-knife nearly caused me the unpleasant position of 
 being covered by several tons of gravel. . . . Having duly 
 reported my find to Professor Putnam, I began at his request a 
 thorough examination of the locality, and on May 25, 1888, 
 the year following, discovered another implement, four feet 
 below the surface, at a place about one eighth of a mile from 
 the first discovery. . . . The geological formation at which 
 the implement was found seems to be a reddish gravel mixed 
 with schist. 
 
 The implements thus discovered by Mr. Cresson in this 
 early deposit of the Glacial period must be connected with 
 others near by, found by him several years before in a shel- 
 ter-cave, since destroyed by the railroad excavation. This 
 was situated near the small building that appears at the right 
 of our picture.* Interested as a youth in the reports of 
 cave explorations in Europe, he carefully excavated this rock 
 shelter in 1866, making notes of and preserving everything 
 he found. As recorded at the time, the lower part of this 
 cave was filled to a depth of about six feet with a deposit ap- 
 parently identical with the Philadelphia red gravel and brick- 
 clay. This contained only palaeolithic implements of argil- 
 lite similar to those (figured on the following page) from the 
 railroad cut near by. Argillite implements, mingled with 
 others of jasper, quartzite, and bone, with fragments of pot- 
 
 * See Fig. 183, p. 670; also "Proceedings of the Boston Society of Natural 
 History," vol. xxiv, p. 145. 
 
674 
 
 TEE ICE AGE IN NORTH AMEEICJL 
 
 tery and hnman bones and charcoal, were found nearer the 
 surface. The total depth of the deposit was about fifteen feet. 
 
 Fig. 185.— ArgnlHte implement, found by H. T. Cresson, 1887, in Baltimore and Ohio Rail- 
 road cut. one mile from Claymont, Delaware, in Columbia Erravel, ciuht to nine feet 
 below the overlying clay bed", f/, face view ; 6, side view. (>'o. 4,5,T~tl ) iPutnam.) 
 
 The progress of the race from the Palaeolithic to the Neo- 
 lithic age here suggested corresponds in part to that indicated 
 by Dr. Abbott's discoveries at Trenton, -where the transition 
 from the palasolithic type of implement to the more modern 
 types, though sudden at the top of the gravel itself, is gradual 
 from the top of the gravel to the surface of the soil. For, 
 according to him,* argillite implements occur in greatest 
 
 * " Proceodinfrs of the .\,inerican .Association for the Advancement of Sci- 
 ence,'" vol. xxxvii. 
 
MAN AND THE GLACIAL PERIOD. 675 
 
 abundance at the base of the deposit of " black soil " which 
 overlies the gravel to an average depth of about one foot< 
 " The flint implements known as Indian relics belong to this 
 superficial or black soil," and they are found abundantly on 
 the surface, more sparingly near the surface, and "more 
 sparingly still the deeper we go," until, on reaching the 
 gravel proper, they disappear entirely. 
 
 In this connection it is interesting to note that at the 
 mouth of Naaman's Creek, the nearest point on the river from 
 the shelter-cave just described, Mr. Cresson has also discovered 
 remains of prehistoric wooden structures below the level of 
 low tide. These consist of the ends of rude piles which had 
 evidently been fashioned by stone implements, but for what 
 purpose intended it is not evident. In dredging here, he 
 found numerous rude argiUite implements of the palseolithie 
 type, which, in the vicinity of two of the structures, were 
 mingled with those of a modem type. 
 
 Thus the valley of the Delaware would seem to contain 
 a record of the passage of the race on the Atlantic coast 
 from the Palseolithie to the Neolithic age. Here, about as 
 far below the ice-front at that time as the shore of Greenland 
 now is, the hardy hunters who had been driven before the 
 advancing cold of the great Ice age found ample space for 
 their pursuits, and excellent shelter in the dense forests which 
 everywhere bordered the southern front of the great snow- 
 fields. The proximity of the ocean furnished, doubtless, a 
 supply of fish, while numerous animals, long since extinct in 
 this region, were for a time fellow-fugitives with man from 
 the advancing northern foe. Among these companions of 
 man we may pretty certainly include the mastodon (one of 
 whose tusks, as already remarked, was found by Professor 
 Cook in the Trenton gravel itself), the walrus, the Greenland 
 reindeer, the caribou, the bison, the moose, and the musk-ox, 
 for the remains of all these animals are fomid either in the 
 superficial gravel deposits of southern New Jersey, or in the 
 adjoining region of country to the south and west. The 
 picture of human life during that period in the valley of the 
 
676 TEE ICE AGE IN NORTE AMERICA. 
 
 Delaware is substantially the same as that presented by the 
 archaeologists of Europe for southern England and northern 
 France in the declining years of the Glacial period. 
 
CHAPTER XXIII. 
 
 MAN IN THE MISSOURI VALLEY. 
 
 Professor, N. H. Winchell* has given a complete list of 
 human remains supposed to have been found in the loess of 
 the Missouri Valley, which belongs to the deposits of the 
 lowan stage of the glacial recession. But so much uncertainty 
 surrounds several instances of these that it will be sufficient 
 to mention only three of the best authenticated and most 
 significant cases, viz., those found at Lansing, Kansas, and 
 at Florence near Omaha, Nebraska, and at St. Joseph, Mis- 
 souri. 
 
 The important discovery at Lansing, Kansas, was made in 
 February 1902, by Mr. Martin Concannon while excavating 
 a tunnel underneath his residence, and was brought to the 
 notice of the public by Mr. M. C. Long of Kansas City, Mis- 
 souri. The skeleton was found seventy-two feet from the 
 moutl\ of the tunnel. The excavation was carefully and 
 re'peatedly examined by various expert geologists, including 
 Professors T, C. Chamberlin, R. D. Salisbury, S. W. Williston, 
 E, Haworth, N. H. Winchell, Warren Upham and W. H. 
 Holmes. I can also speak from careful personal inspection 
 of the whole locality. Subsequently also Mr. Gerard Fowke 
 and Mr. Long were engaged by Mr. Holmes to dig a cross 
 section strikiiig the tunnel near the place where the skeleton 
 was found. The unanimous testimony was that the remains 
 occurred as reported in undisturbed loess. In fact several 
 other less important human relics were found by Mr. Fowke 
 in his excavations. 
 
 • "Records of the Past," vol. vi (May 1907), pp. 148-157. 
 
MAN IN THE MISSOURI VALLEY. 
 
 679 
 
 The only questions as to the glacial age of the relic is 
 whether this remnant of loess belongs to the original deposit 
 connected with the lowan stage of glacial recession, or whether 
 it may not have been re-deposited at some later stage of 
 river erosion. Professor Chamberlin maintained that it was 
 a secondary deposit, and that its antiquity "is measured by 
 
 GEOLOGY 
 
 OF THE CONCANNON FARM 
 
 The Region iscovered by 'the lowan Loess 
 With Kansan DrHt on the Uplands. 
 
 ■' Ce»eANNOff '' 
 a 
 
 
 '"'"■^•fy/Sieiiof''" 
 
 
 SCALE 
 One Half Inch = lOQ Feet. 
 Fia. 187. 
 
 
 ;!§• 
 
 the time occupied by the Missouri River in lowermg its bot- 
 tom, two miles more or less in width, somewhere from fifteen 
 to twenty-five feet, a very respectable antiquity, but much 
 short of the close of the glacial invasion."* But after three 
 visits to the locality. Professor Winchell seems to show con- 
 clusively that the loess belongs to the original undisturbed 
 
 • "Journal of Geology," October-November, 1902. 
 
680 THE ICE AGE IN NORTH AMERICA. 
 
 deposit of lowan age. My own personal investigations on 
 the ground amply sustain this view as will appear from study of 
 the accompanying illustrations. 
 
 The remnant of loess is protected on a rocky promontory 
 left between the main valley of the Missouri and a small 
 stream whose channel dates from preglacial times. The 
 stratum near the bottom of the tumiel in which the skeleton 
 was found is between eleven and twelve feet above the extreme 
 present highwater mark of the river, while the loess overlying 
 the skeleton is twenty feet thick ; and loess underlies the house 
 
 Fig. 188 — Vlsw showins: entrance to tunnel In which the Lansing Skeleton was found 
 (Courtesy of Records of the Past.) 
 
 still several feet higher, and mantles the narrow slope well 
 up to the 200 foot level constituting the loess plain which 
 furnishes the location for the city of Leavenworth, a short 
 distance away. West of the tunnel, also, the loess slopes 
 rapidly upwards to the same level. 
 
 The most conclusive witness to the original and undis- 
 turbed character of the deposit in which the tunnel was exca- 
 vated will be seen from a study of the accompanying map. 
 The bottom of the tunnel is on a rock exposure of limestone 
 whose outcrop extends from B to the side ravine, where, after 
 a short iaterruption, it appears on the other side westward to 
 
MAN IN THE MISSOURI VALLEY. 
 
 681 
 
 A, where the main tributary creek descends from the apex of 
 a rocky gorge into what is evidently a preglacial portion 
 extending 500 feet from A to C. There is no rock visible in 
 
 Fig. 189 — Front \- lew of ^kul land femur bones uf Lansing Skeleton. (Courtesy- of Records 
 of tfie Past.) 
 
 the valley from A to C, and the water which in dry weather 
 comes into its head continually disappears in the gravel 
 underneath, whose surface at the entrance of the tunnel is 
 
 Fig. 190 — Side view of skull and femur bones of Lansing Skeleton. (Courtesy of Records 
 of the Past.) 
 
 twenty feet below the rock exposure, while a well a little farther. 
 east was sunk to a depth of twenty-four feet without striking 
 rock, and the railroad immediately east of the mouth of the 
 
682 THE ICE AGE IN NORTH AMERICA. 
 
 buried gorge is supported by piles driven thirty feet into 
 the alluvium. Above A this ravine lies wholly in the en- 
 veloping loess. 
 
 From this it is evident that the rock erosion in the lower 
 part of the tributary entering at A is neither post-glacial nor 
 interglaeial, but is a remnant of preglacial erosion when the 
 whole region was so much elevated that the river had lowered 
 its bed a considerable depth below that now occupied by it. At 
 Omaha the rock bottom of the river is known to be eighty 
 feet below its present bottom. Since the advent of the con- 
 tinental ice-sheet the preglacial gorge has been aggraded to 
 a considerable extent, and meanwhile, during the lowan stage 
 of the glacial period the loess bluffs of the Missouri Valley, 
 here so pronounced, were deposited on the ever rising flood- 
 plain of the torrents which for many centuries poured out 
 from the melting ice during the closing stages of the epoch. 
 The Lansing skeleton antedates the deposition of the entire 
 loess formation. 
 
 Positive evidence of the aqueous character of the loess 
 overlying the skeleton, was noted by Mr. Upham; namely, 
 a " distinct darker layer of loess mostly about two inches thick 
 but in part merely a threadlike line, traceable continuously 
 through all the seventy-two feet of the west wall of the tunnel, 
 running about three or four feet above the limestone floor, 
 and one foot or a little more above the base of the loess. " 
 This extended in a straight plane descending from south to 
 north about one inch to ten feet. Other lines of nearly horizon- 
 tal stratification were also observed, thus clearly showing that 
 it is an aqueous deposit of the same character with that of 
 the loess of the whole valley. 
 
 The most plausible suggestion for the later deposition has 
 been made by Professor J. E. Todd,* who thinks it possible 
 that the loess on which the Concannon house stands may be 
 
 * "Recent Alluvial Changes in Southwestern Iowa," "Proceedings 
 of Iowa Academy of Science," 1907, pp. 257-266. 
 
MAN IN THE MISSOURI VALLEY. 683 
 
 the remnant of a cone of dejection brought down from the 
 adjoining loess terrace when the Missouri River was flowing 
 on the opposite side of the trough, two miles distant. Some 
 remarkable facts are given by him of the rapid growth of 
 such cones in the Missouri Valley opposite Nebraska City, 
 since the occupation of the country 'by whites. But the fact, 
 just stated concerning the slight northward dip of the strati- 
 fication noted by Dr. Upham, and the extent to which the 
 remnant of the deposit runs up the ridge back of the house to- 
 wards the main terrace would seem to render Professor Todd's 
 theory incredible. 
 
 As to the skeleton itself, it so much resembles that of some 
 modern American Indians, that the Americanists who exam- 
 ined it at the International Meeting in New York, in the 
 autumn of 1902, and later Professor Holmes and Mr. Hrdlicka 
 think it incredible that it can be of glacial age. Their opinion, 
 however, is largely discounted by the fact that greatly exag- 
 gerated ideas of the antiquity of the glacial epoch are enter- 
 tained by most of these experts. When the evidence is made 
 to show that the date of the lowan glacial episode did not 
 close until about the time that the civiUzation of Egypt, 
 Babylonia and Western Turkestan had attained a high degree 
 of development, and that the cranial capacity had at that 
 time in those regions reached that of the higher races of the 
 present time, there would seem to be little dependence to be 
 put upon d priori dicta adverse to the glacial age of the Lansing 
 skull. 
 
 The remains of the Nebraska Loess-Man were discovered 
 in the summer of 1906, by Mr. Robert F. Gilder, who soon 
 after called in Mr. E. H. Barbour, Professor of Geology in 
 the University of Nebraska to make more extended investi- 
 gations and give an expert opinion as to the age of the deposit. 
 
 The locality of this discovery is in the township of Florence 
 on the western loess bluffs of the Missouri River a few miles 
 aboveOmaha. Herefrom ten to twentyfeet of glacial driftrest- 
 
684 
 
 THE ICE AGE IN NORTH AMEHICA. 
 
 ing on a stratum of carljoniferous limestone, is overlaid hj 150 
 feet of loess, making the elevation above the river 200 feet. 
 Near the surface there were found manj^ relics indicating 
 recent interments. But at lower depths, reaching in some 
 cases eleven and a half feet, bits of bone were found. Be- 
 low a depth of five feet there was no evidence that the loess 
 
 Fio. 191 — Section of Lore's Hill, Nebraska. The man la pointing to the base of the loess 
 resting upon 40 feet of till. (Courtesy of Records of the Past. ) 
 
 had been disturbed subsequent to its deposition, since here 
 the characteristic vertical lime tubes and concretions were 
 every^vhere present. Moreover the fragments of bones were 
 widely scattered, only five or six fragments being found to a 
 cubic yard, and some of these evidently were water worn. The 
 prize specimen was that of a skull broken, disarticulate and 
 
MAN IN THE MISSOURI VALLEY. ■ 685" 
 
 scattered over a space of twenty-five square feet, between four 
 and five deep in the undisturbed loess. The walls of this 
 were thick, measuring as much as three-eighths of an inch. 
 Counting all the fragments. Professor Barbour estimates that 
 there are probably ten or twelve individual skulls represented 
 in this loess bone bed and that comparison shows them to be 
 of the Neanderthal type, with thick cranial walls.* 
 
 We are bound to say, however, that the glacial age of these 
 relics, like everything else of much moment in scientific dis- 
 covery, has been disputed by high authorities. In this case it has 
 been done by Professor B. Shimek,t an accomplished investi- 
 gator of land shells. From study of these in the loess deposi bs 
 of the region he has become an ardent advocate of the seolian 
 hypothesis respecting the distribution of loess, and hence 
 approaches the question with the bias of that theory. For 
 a general discussion of the seolian hypothesis the reader is 
 referred to the chapter on the Loess. It is sufficient to say here 
 that it is hardly possible that so experienced an authority as 
 Professor Barbour, and one so familiar with the loess of the 
 region could be mistaken in the matter. His excavations 
 were extensive, and most carefully made, and his conviction 
 of the undisturbed character of the portion of the deposit in 
 which the remains were found was unequivocal. Professor 
 Shimek's judgment in the case is also greatly discounted by 
 his equally positive, but certainly, erroneous opinion that the 
 deposit in which the Lansing skeleton was found was cleiarly 
 distinct from ordinary undisturbed loess, ' ' evidently consisting 
 of slumped material." In short there is no valid reason to 
 doubt the glacial age of the loess in which the remains of the 
 Nebraska man were found. 
 
 The relic described by Miss Owen is an implement of 
 paleolithic type, chipped from a porphyritic pebble (probably 
 
 * "Nebraska Geological Survey," vol. ii, part 5, pp. 318-327; part 6, 
 pp. 331-348. Also "Records of the Past," vol.VI, Feb. 1907, pp. 34-39. 
 
 t "Bulletin of Geological Society of America," vol. xix, pp. 243- 
 254, 1908. 
 
686 
 
 THE ICE AGE IN NORTH AMERICA. 
 
 from the Black Hills, Dakota). The illustration speaks for 
 itself. This was found projecting from the face of an old 
 cut for a road through the loess in the northern part of the 
 city of St. Joseph, Missouri . It was found not less than twenty 
 
 l-Vi;: 
 
 Fig. 192— Implement from PiiK HlII. (Miss Owen). 
 
 feet below the surface where there could be no question con- 
 cerning its undisturbed character. This is on the east side of 
 the Missouri River, where the total depth of the loess is more 
 
 tha n 100 feet.* 
 
 * "Records of tlie P;tst," October. 1007, pp. 28fi-292. 
 
CHAPTER XXIV. (Concluded). 
 
 MAN AND THE LAVA BEDS OP THE PACIFIC COAST. 
 
 The occurrence of human relics in the auriferous gravels 
 of California, where in some places they are capped with ex- 
 tensive lava overflows, though still a subject under hot 
 discussion is too important and interesting to be passed over 
 without a full detail of the facts. The connection of these 
 facts with the glacial epoch, though inferential, is by no means 
 uncertain; for, confessedly, the lava flows west of the Rocky 
 Mounta,ins, though commencing early in the tertiary period, 
 have continued in great volume down to very recent times, 
 some extensive eruptions having occurred in California and 
 Idaho within the last two or three hundred years; while the 
 remains of extinct animals found in the auriferous gravels are 
 substantially the same as to be found in the glacial deposits 
 of the eastern United States and Europe. At the same time 
 the indications are clear that the glaciers of the Sierras in 
 California and elsewhere extended greatly beyond theirpresent 
 limits down to a period of time separated from us by only a 
 few centuries. Nor should the existence of unbelief, on the 
 part of many, prevent a candid consideration of the facts, 
 for it is pre-eminently a question of evidence such as is em- 
 ployed in all historical investigations, and so, open to chal- 
 lenge. But we are convinced, it is beset with difiiculties 
 no greater than pertains to all investigations of a similiar 
 nature. 
 
 The incredulity prevailing concerning these facts will 
 largely disappear upon consideration of the evidence of re- 
 
688 THE ICE AGE IN NORTH AMERICA. 
 
 cent activity of volcanic forces on the Pacific Coast, and of 
 the recency of the disappearance of the glaciers from the 
 mountains of the region. All competent observers have re- 
 marked the freshness of the lava deposits in the Snake river 
 Valley in Idaho, while Mr. Diller* has shown that in the 
 great interior basin in California near Lassen Peak, between 
 Snag Lake and Lake Bidwell, there is a region many miles in 
 extent covered with lava and volcanic ash to a uniform depth 
 of many feet, with cones rising more than 600 feet, all of which 
 must have been ejected within the last 200 years. Stumps 
 of trees are still projecting from the stratmn of volcanic ash 
 which killed them, while the charred trunks of other trees 
 which were overwhelmed by the lava stream still remain 
 undecayed. It is impossible that these trunks could have 
 resisted the corroding agencies even of this dry atmosphere 
 for many centuries while none of the fresh trees growing on the 
 surface of the stratum of volcanic ash are more that 200 years 
 old. 
 
 It should be remembered also that the vast erosion since 
 the auriferou gravels were covered by lava was hastened by 
 the enormous floods which occurred when the glaciers which 
 had been subsequently formed melted off. The floods aris- 
 ing from the annual melting of the snow in the region are now 
 enormous. How much greater must they have been in the 
 decUning years of the Glacial Epoch! 
 
 The first evidence upon the point to which we will turn 
 attention is that produced by Professor J. D. Whitneyt of 
 Harvard University, concerning human remains believed by 
 him to have been found in strata which mark the closing 
 period of the Tertiary epoch in California. 
 
 The following description of the deep placer deposits in 
 which these remains have been found is given by Le Conte: 
 
 * See "Bulletin of U. S. Geol. Survey," No. 79, 1891. 
 
 t "Report on the Auriferous Gravels of the Sierra Nevada," 1879, 
 p. 258 et seq. 
 
MAN AND THE LAVA BEDS. 
 
 689 
 
 There are in many parts of California two systems of river- 
 beds, an old and a new. The old belongs to the Tertiary ; the 
 new, to the Quaternary and present. The change took place 
 during the oscillations of the Quaternary. The old river-system 
 is substantially parallel to the present river-system, though in 
 some places the one cuts across the other. It is probable, 
 therefore, that there was but little change in the general direc- 
 tion of the slope, produced by the oscillations of this epoch. 
 These old river-beds are filled with drift-gravel, and often cov- 
 ered with lava-streams. These drift-gravels probably repre- 
 sent the beginning of the Glacial epoch, though Whitney 
 thinks an earlier or Pliocene epoch. The present river-system 
 sometimes cuts across, sometimes runs parallel to, the lava- 
 filled beds of the old river-system, and the beds of the former 
 have in their turn been eroded two thousand to three thousand 
 feet in solid rock. In these also have been accumiilated im- 
 mense quantities of gravel and bowlder drift, evidently brought 
 
 FiQ. 193.— Lava-stream cut through by rivers ; a, a, basalt : 6, 6, volcanic ashes ; c, c, ter- 
 tiary ; d. d, cretaceous rocks ; ij, B^ direction of the old river-bed ; R', i?', sections of 
 the present river-beds. (Le Conte from Whitney.) 
 
 down from' the glacial moraines by the swollen rivers of the 
 Champlain and early Terrace epochs. These facts are illus- 
 trated by Figs. 193 and 194, in which R' represents the present 
 
 Fig 194 —Section across Table Monntain, Tuolumne County, California, d, lava ; O, grav- 
 el ; «, slate ; S, old river-bed ; E', present river-bed. (Le Conte.) 
 
 river-system, in Fig. 193, cutting across, and in Fig. 194 run- 
 ning parallel to, the old system R. 
 
 Although it is impossible to synchronize with certainty 
 
690 THE ICE AGE IN NORTH AMERICA. 
 
 these events with the changes in the eastern portion of the 
 continent, yet the order of sequence is evident ; and that the 
 greater part, if not all, occurred in the Quaternary, is also evi- 
 dent. . . . 
 
 The history of changes shown in these sections is suffi- 
 ciently obvious. In the time of the old river-system, R was a 
 river-bed, doubtless with a ridge on either side represented by 
 the dotted lines. In this bed accumulated gravel, containing 
 gold. Then came the lava-flow, which of coarse ran down the 
 valley, displacing the river and covering up the gravels. The 
 displaced rivers now ran on either side of the resistant lava, 
 and cut out new valleys, two thousand feet deep, in the solid 
 slate, leaving the old lava-covered river-beds and their aurifer- 
 ous gravels high up on a ridge. In other cases the convulsion 
 which ejected the lava also changed greatly the general slope 
 of the country, and therefore the direction of the streams. In 
 such cases of course the present river-system cuts across the 
 old river-beds and gravels, and their covering lavas, as shown 
 in Pig. 142. 
 
 The age of the old river-gravels is still doubtful ; that of 
 the newer river-gravels is undoubtedly Champlain or early Ter- 
 race. Below we give a list, taken from Whitney, of the re- 
 mains found in these gravels : 
 
 Newer Placers. — Great mastodon, mammoth, bison, tapir 
 (modern), horse (modem), man's works. 
 
 Deep Placers. — Great mastodon,* mammoth, tapir (mod- 
 ern), rhinoceros (ally), hippopotamus (ally), camel (ally), horse, 
 extinct species. 
 
 It will be seen that the fauna of the deep placers unite Pli- 
 ocene and Quaternary characters. The great mastodon, the 
 mammoth, and the tapir, are distinctively Quaternary, while 
 the others are Pliocene. The plants, according to Lesqnereiix, 
 are decidedly Pliocene. Therefore Whitney has not only placed 
 the deep placers in the Pliocene, but made them the repre- 
 sentative of the whole Pliocene, and probably Miocene, and 
 the lava-flow as the dividing-line between the Tertiary and the 
 
 * Whitney states that the mastodoo is not found here, but it has been 
 since found. 
 
MAN AND THE LAVA BEDS. 691 
 
 Quaternary. But, all the facts considered, it seems most prob- 
 able that both the filling of the old riyer-beds, and their pro- 
 tection by lava, took place comparatively rapidly, and were 
 together the closing scene of the Tertiary drama. The deep 
 gravels, therefore, may be placed indifferently in the latest 
 Pliocene or earliest Quaternary. The newer gravels are un- 
 doubtedly Quaternary and recent. Certain it is that the deep 
 placer-gravels are similar in all respects to the Quaternary 
 gravels all over the world, except that, by percolating alkaline 
 waters containing silica, they have been cemented in some 
 eases into grits and conglomerates. This is because they are 
 covered with lava which yields both the alkali and the soluble 
 silica. 
 
 In any case, we have here an admirable illustration of the 
 immensity of geological times. The whole work of cutting 
 the hard slate-rock two thousand feet or more has been done 
 since the lava-flow, and therefore certainly since the beginning 
 of the Quaternary.* 
 
 It will readily be seen that these upper gravels, whether 
 we call them Tertiary or Quaternary, are with reference to 
 the historical period very ancient, though reoent if spoken 
 of from a geological point of view. The question of man's 
 antiquity does not turn on the name of the formation ; but 
 upon the reality of the existence of his remains in the upper 
 gravels. Indeed, there does not seem to be any hard-and- 
 fast line of demarkation between the Tertiary formation and 
 the Quaternary, or recent. In making chronological calcula- 
 tions from the vast amount of erosion spoken of in the pre- 
 ceding paragraph, Le Conte warns us, however, to note the 
 prodigious rapidity with which erosion now proceeds in con- 
 nection with hydraulic mining. " In the North Bloomfield 
 mine, the pebble-loaded torrent resulting from the incessant 
 play of the hydraulic jet against the clifif, though working 
 but eight months per yeai*, has cut in four years a channel 
 three feet wide and fifty feet deep in solid slate." f 
 
 » Le Conte's "Elements of Geology," 1888, pp. 555, 585. 
 
 f ■• Ameiicaii .Toiirnal of Science," March, 1880, vol. cxix, p. 179. 
 
692 THE ICE AGE IN NORTH AMERICA. 
 
 Unfortunately, the evidence that human remains have 
 been taken from beneath these lava-capped mountain-ridges 
 is neither of recent date nor that of professed geologists. 
 We are compelled to depend upon the testimony of plain 
 miners, exhibiting what they found and recounting what 
 they saw several years ago. This fact, which needs expla- 
 nation, is said to arise from the wholesale changes in the 
 methods of mining introduced by hydraulic processes. By 
 present methods terraces are washed down into a promiscu- 
 ous heap by jets of water forced against them with great ve- 
 locity, so that there is little hope of finding the archaeologi- 
 cal specimens they may have contained. The golden days 
 for the archaeologist in California have passed by. Still, so 
 many independent witnesses from different localities have 
 testified to the facts which we now relate, and circumstantial 
 evidence so fully corroborates the statements of the witnesses, 
 that Professor Whitney and his associates think they are be- 
 yond question.* 
 
 As early as 1863 Dr. Snell, of Sonora, began a systematic 
 collection of animal and human remains from the mines in 
 his vicinity. In his collection were several objects marked as 
 " FroTn under Table Mountain," among which was a human 
 jaw. Dr. SneU's collection was destroyed by fire, and he 
 died in 1869 ; but Professor Whitney and Mr. Voy had 
 repeatedly examined it and conversed with him. A stone 
 utensil, apparently used for grinding, was the only one 
 which Dr. Snell claims to have taken with his own hands 
 from the dirt as it came out of the tunnel under the mountain. 
 
 In 1857 Hon. Paul Hubbs, of Vallejo, Cal. (subsequently 
 a State Superintendent of Public Instruction), picked a por- 
 tion of a human skull out of the dirt as it was brought from 
 the Valentine shaft, under Table Mountain, near Shaw's Flat. 
 This skull was given to Dr. C. F. Winslow, who soon after 
 (October 7, 1857) divided it, and sent one piece to the Philar 
 
 * A few paragraphs are here substantially reproduced from my " Studies in 
 Science and Religion," p. 285 el seq. 
 
MAN AND THE LAVA BEDS. 693 
 
 delphia Academy of Sciences and the other to the Boston 
 Society of Natural History, where it still remains, and in 
 whose " Proceedings " (vol. vi, p. 278) Mr. Winslow's original 
 communication may be found. 
 
 Ten years after, Mr. Hubbs more fully detailed the cir- 
 cumstances of the discovery, and Professor Whitney and 
 Gorham Blake, Esq., made special examination of the locality 
 and careful inquiries of the owners of the mine, and satisiied 
 themselves that the bone really came from under the basaltic 
 covering of Table Mountain. Mr. Walton, one of the owners, 
 did not remember anything about the bone, but did remem- 
 ber that a " mortar " had been found in the tunnel, near 
 the same situation. 
 
 In 18T0 Mr. Oliver W. Stevens gave to Mr. Voy a large 
 stone bowl, which was incrusted with sulphuret of iron, and 
 which he makes affidavit that he picked with his own hands, 
 in 1853, from a load of dirt which came from a tunnel under 
 Table Mountain, two hundred feet in, at Shaw's Flat. 
 
 Mr. Llewellyn Pierce also makes affidavit that a certain 
 stone mortar which he gave to Mr. Voy was taken, in 1862, 
 from under Table Mountain, eighteen hundred feet from the 
 mouth of the tunnel. 
 
 All this is preliminary to the famous Calaveras skull, the 
 facts about which are as follows : 
 
 In February, 1866, Mr. Mattison, one of the owners of 
 a claim on Bald Mountain, near Altaville, says he took from 
 a tunnel under the basaltic capping of the mountain an ob- 
 ject which, on account of incrusted earthy and stony ma- 
 terial, he thought at first to be the petrified root of a tree, 
 but which he discovered to be a portion of a skull. He took 
 it to Mr. Scribner, agent of the express company, who, after 
 seeing the importance of the discovery, passed it over to Dr. 
 William Jones of Murphy's, a physician of extensive practice 
 and scientific tastes. Both these gentlemen were well known 
 to Professor Whitney, and their veracity is vouched for by 
 him. The skull was forwarded by Dr. Jones to the office 
 of the State Survey on the following June (1866). Mr. Mat- 
 
694 THE ICE AGE m T^WRTM AMERICA. 
 
 tieon haiS^ been repeatedly interviewed, and his testimony is 
 uriifbrmly coherent and explicit, to the! effect that he took 
 the skull with his own hands from gravel underneath a cap- 
 ping of forty feet of black lava and in connection with drift-" 
 wood. The appearance of the skull in every way corrobo- 
 rates his statement. The original incrustation shows that it 
 was not taken from a cave. The late Dr. Wym^n, of Harvard 
 College, and Professor Whitney together carefully removed 
 the incrustations from the skull. Fragments of bones and 
 gravel and shells were so wedged into the cavities of the 
 skull as to satisfy them that there could be no mistake as to 
 the character of the situation in which it was found. Chemi- 
 cal analysis showed that organic matter was nearly absent, and 
 the carbonate of lime had largely displaced the phosphate ; 
 i. e., it was in a fossilized condition. 
 
 In a visit to Sonera, California, and to Bald Mountain, where 
 tlie Calaveras skull was discovered, I was so fortunate also 
 myself as- to run upon evidence of a previously unreported 
 instance of the discovery of a stone mortar under Table Mount- 
 ain, The mortar was found in October, 1887, by Mr. C. 
 McTarnahan, the assistant surveyor of Tuolumne county. It 
 was lying in the gravel reached by the Empire Tunnel, and 
 about a mile west of the Valentine shaft mentioned on page 
 692. This tunnel had been excavated 758 feet before reaching 
 the gravel, and the mortar was found 175 feet in a horizontal 
 line from the edge of the Table Mountain basalt, and about 100 
 feet below the surface. The object was taken out and laid 
 beside the mouth of the tunnel, and was given to Mrs. M. J. 
 Dai-win, of Santa Rosa, Cal., who has given it to me. The 
 mortar is made from a bowlder of some eruptive rock, and is 
 six and a half inches through ; the hollow being about three 
 and a half inches ifa diameter, and about three inches deep. 
 
 "This mortar is now in possession of the Western Reserve 
 Historical Society of Cleveland Ohio. An account of the 
 discovery was given to the Geological Society of America, at 
 Washington, in 1891. 
 
 At the same meeting Mr. George F.' Becker of the U. S. 
 Geological Survey, presented the affidavit of Mr. John H. 
 
MAN AND THE LAVA BEDS. 695 
 
 Neale, a mining engineer of much experience and high reputa- 
 tion, to the effect that in 1877 while running the Montezuma 
 tunnel into the gravel underlying the lava of Table Mountain, 
 Tuolimme County, near Rawhide Gulch, and when 1,400 feet 
 from the mouth of the tunnel and between 200 and 300 feet 
 from the edge of the solid lava, he found several spear heads 
 of some dark rock and nearly one foot in length, and, near by, 
 two mortars and a pestle. 
 
 "Mr. Neale declares it utterly impossible that these relics 
 can have reached the position in which they were found ex- 
 cepting at the time the gravel was deposited, and before the 
 lava cap formed. There was not the slighest trace of any 
 distiirbance of the mass or of any natural fissure into it by 
 which access could have been obtained either there or in the 
 neighborhood . " * 
 
 With regard to this evidence Mr. Becker justly remarked 
 that the mining engineer is of all persons in the world best 
 fitted to determine whether the gravel in such a tunnel had 
 been disturbed, for the chief danger in such mining arises 
 from penetrating old drifts. Therefore a geologist would 
 rather trust an engineer's testimony in such a case than his 
 own. 
 
 The only reason found by Mr. Sinclair (whose general 
 criticisms will be given later) for doubting the facts as here 
 stated arises from the circumstances that the mortar of 
 andesiteand the spear heads of obsidian are found in pre- vol- 
 canic gravels. But this obj ection overlooks the fact that there 
 was extensive commerce between the aboriginal tribes, and 
 that the outflows of lava were by no means contemporaneous 
 in different parts of the Pacific coast. Obsidian, for example, 
 is found in large quantities in the mounds of Ohio, two thou- 
 sand (2000) miles from any original deposit of the material. 
 
 Another bit of evidence from the same vicinity was pre- 
 sented by Mr. Becker at the same meeting of the Geolpgical 
 
 * "Bulletin of Geological Society of America," vol. ii, p. 192. 
 
696 THE ICE AGE IN NORTH AMERICA. 
 
 Society. This was a broken pestle found by Mr. Clarence 
 King and taken with his own hands from vindisturbed gravel 
 under Table Mountain in the vicinity of Tuttletown not 
 far from Rawhide Gulch. As Mr. King was a geologist of 
 the highest reputation this would seem to be convincing 
 evidence. But it is suggested that he may not have given 
 attention to the question whether there had not been secondary 
 cementation of the gravel, so that this may possibly have 
 been in a talus. It is, however, hardly to be supposed that so 
 experienced a geologist as Mr. King would have failed to 
 notice a point of so much importance. 
 
 As already remarked the fact that new discoveries do not 
 continue to be made in the auriferous gravels is readily ac- 
 counted for from the fact that the profitable mines where such 
 relics would be likely to be found have been worked out, and 
 hence such mining has ceased. 
 
 The gravels under Table Mountain have not yielded enough 
 gold to pay for the mining, and hence have been abandoned, 
 while hydraulic mining so mingles the dibris washed down that 
 the discovery of implements in place is practically out of 
 the question. Still, important discoveries do now occur. 
 
 In "Science" for March 6, 1906, Mr. J. F. Kemp, of the 
 U. S. Geological Survey, reported the discovery of mortars and 
 pestles in the auriferous gravels at Waldo, Josephine County, 
 Oregon. The discoveries which he reports were made in 1901 
 and 1902. The latter was brought out by the miners during 
 the night shift from 58 feet below the surface, where it was 
 embedded in "the blue cement gravel " of the " pay channel." 
 So firmly was it embedded that they had to resort to picks 
 to extricate it and I'the bed or hole out of which they pulled 
 itremained, showiagitsperfectmould. "inthemoming," says 
 Mr.W. J. Wimer, the manager (who carefully noted the facts), 
 "it was still packed tightly to its very rim with blue cement 
 gravel "which after being carefully picked out yielded several 
 "large colors of gold." The mortar is about twelve inches 
 
MAN AND THE LAVA BEDS. 697 
 
 high by nine inches across, and is made of the hardest granite. 
 Pestles were found in this deposit often enough to cause no 
 surprise. In 1901 another mortar with some pestles had been 
 found ten feet under the surface and about 300 yards from this 
 in the same "pay dirt."* 
 
 Fia. 195 — McTarnahfiii Mortar from under Table Mountain 
 
 We omit mention of a large number of human remains 
 found at great depths in the ancient higher-level gravel where 
 not covered with lava, though some of them are doubtless of 
 tJie same age with those from under Table Mountain. 
 
 According to Professor Whitney, the evidence " all 
 points in one direction, and there has never been any at- 
 tempt made to pass off on any member of the Survey any- 
 thing out of keeping or, so to speak, out of harmony with 
 what has been already found, or might be expected to be 
 found. It has always been the same kind of implements 
 which have been exhibited to us — namely, the coarsest and 
 the least finished which one would suppose could be made, 
 and still be implements at all." This result, he cogently re- 
 marks, would hardly be possible where so many parties are 
 concerned in furnishing the evidence, if the objects were not 
 genuine, and shows to his mind that the evidence has not 
 been got up to deceive. 
 
 As might be expected, strenuous efforts have been made 
 to discredit these facts. With reference to the Calaveras 
 skull, we read in Dr. Southall's "Recent Origin of Man" 
 (p. 558) that " Dr. Andrews inform" is [Dr. Southall] that 
 the Eev. K. W. Patterson, D. D., of Chicago, tells him that 
 
 'Records of the Past" vol. v, June, 1906, pp. 190-191. 
 
698 THE ICE AGE IN NORTH AMERICA. 
 
 he was informed by the Rev. W. W. Brier, a reliable minister 
 of Alvarado, Cal., that his [Brier's] brother, a miner, was 
 one of two men who took the so-called Calaveras skull from 
 a cave in the side of the valley, and placed it in the shaft, 
 where it was found, and that the whole object was a prac- 
 tical joke to deceive Professor Whitney, the geologist." 
 Whether this is probable can be judged from the foregoing 
 statement of facts as since detailed by Professor Whitney. 
 At any rate, it would have been the proper thing for this 
 renegade brother of the Rev. Mr. Brier to have submitted 
 himself to closer cross-examination from competent parties 
 than he seems to have done. 
 
 Sir William Dawson and others have questioned whether 
 these human remains might not have been introduced at a 
 period subsequent to the deposition of the gravel and the 
 overflow of the lava. They have suggested that the Indians, 
 in searching for gold, may have run horizontal shafts into 
 the gravel underneath ; or, since the lava is not compact but 
 tufaceous in its character, it does not seem impossible that, 
 in some places, pits may have been sunk from the surface. 
 
 The most formidable opposition to Professor Whitney's 
 conclusions comes, curiously enough, from evolutionists, so 
 that, upon this question, they are now found "among the 
 prophets." The thorough-going evolutionist believes that 
 early man was ape-Uke in his features, and that he invariably 
 passed through a stage in which he used rough stone imple- 
 ments before learning to polish them. But the Calaveras 
 skull, which, if genuine, far antedates anything human 
 which has been discovered in Europe, is not of a particularly 
 inferior order, and the implements purporting to come from 
 under Table Mountain are not of the palaeolithic type, but, 
 though exceedingly coarse and rude, correspond to those of 
 the smooth stone period in Europe. Professor Putnam, 
 however, suggests,* and Professor A. Winchell is ready to 
 
 * " Report of the United States Greological Surveys west of the One Hun- 
 dredth Meridian,'' vol. vii, pp. 10-15. 
 
MAN AND THE LAVA BEDS. 699 
 
 admit,* that man waudered into California long before he 
 entered Europe, and attained there the higher state of devel- 
 opment reached by palaeolithic man in other parts of the 
 world at a much later date. 
 
 The objection to Professor "Whitney's inferences arising 
 from the possibility that the aboriginal inhabitants of that 
 region themselves carried on mining operations for the sake 
 of obtaining this gold is presented, in a convincing manner, 
 by Dr. James Southall. According to him,t Bancroft, in 
 his " Native Eaces of the Pacific States," refers to it as a 
 well-known fact that mining operations were carried on in 
 Mexico to a great extent, opening galleries into the solid 
 rock, in some cases two hundred feet or more in depth ; and 
 Schoolcrait, in his " Archaeology," :]; describes one of these 
 ancient shafts, which was discovered in 1849. This was two 
 hundred and ten feet deep, and its month was situated on. a 
 high mountain. "The bones of a human skeleton were 
 found at the bottom. There were also found an altar for 
 worship and other evidencess of ancient labor." 
 
 It is to be observed that, in the quotation from School- 
 craft made by Bancroft, it is stated that " no evidence has 
 been discovered to denote the era of this ancient work. There 
 has been nothing to determine whether it is to be regarded 
 ■as the remains of the explora,tions of the first Spanish advent- 
 urers, or of a still earlier period. The occurrence of the re- 
 mains of an altar looks like the period of Indian worship." 
 Professor Putnam, however, writes me : " I think there is a 
 strong objection to the ancient mining theory, inasmuch as 
 we do not know of gold among the Oalifomian Indians. The 
 Mexicans had it, but did they mine it in California ? The 
 stone mortars we find in the California gravels are not of 
 Mexican type, but of OaUfomian type, the same form used 
 in recent times." 
 
 * "Pre- Adamites," p. 428. f "Plibcene Man in America," p. 7. 
 
 t Vol. i, p. 105. For a full summary of facts see Bancroft's "Native Racea 
 of the Pacific States," vol. iv. 
 
700 THE ICE AGE IN NORTH AMERICA. 
 
 A more serious arraignment of this whole evidence is 
 made by Professor W. J. Sinclair of Berkely, California. 
 It is unnecessary to review the whole of Mr. Sinclair's 
 argimient in detail. But in general it is sufficient to say that 
 it is mainly occupied with throwing doubt upon the sufficiency 
 of the evidence in each of the many individual cases of alleged 
 discovery reportedby Professor Whitney and others, but fails 
 to break the f.orce of the cumulative evidence arising from the 
 great number of instances. For, it is highly improbable that 
 so many cases each with so great probability would have been 
 fabricated from such widely separated places. The theory of 
 fraud in so many separate instances agreeing in the main 
 point of contention yet differing so much in detail is exceed- 
 ingly improbable. While the supposition that the gravels 
 xmderneath the lava deposits had been previously worked 
 over almost the whole area, is equally improbable. 
 
 But in particular it must be admitted that there has been 
 a mistake in respect to the Caliveras skull reported to have 
 been found by Mr. Mattison. The skull examined by Pro- 
 fessors Whitney and Wyman and now in possession of the 
 Peabody Museum of Harvard University evidently did not 
 come from under the lava deposits described by Whitney as 
 occurring at Bald Hill. For, Mr. Sinclair's examination of 
 the skull and of the incrustation enveloping it shows that it 
 must have come from some cavern in the vicinity used by 
 the Indians as a sepulcher. Hence it follows that if Mr. 
 Mattison actually took a skull from his drift under Bald Hill 
 some other skull must have been substituted for it in the 
 course of transmission. That this could have been done under 
 ■the circumstances without impeaching the honor of any of the 
 parties involved is readily seen from a fuller statement of 
 some of the circumstances. Such, at any rate is the opinion 
 of Professor Putnam. (See Sinclair's paper above quoted, 
 p. 129). In confirmation, I may state that in 1890 when I 
 visited Mr. Scribner he gave me the story substantially 
 
M^JV AND THE LAVA BEDS. 701 
 
 as Professor Whitney relates it, but with some additional details 
 bearing specially upon the points here raised though they had 
 not been raised at that time. He said to me that when he 
 gave the skull to Dr. Jones, soon after Mr. Mattison had given 
 it to him, he was not able to furnish the particulars to the 
 Doctor, as at the time he was not impressed with its impor- 
 tance. Dr. Jones, therefore, put it outside his office, with 
 other collections of a similar sort, where it lay for several 
 months until Mr. Mattison came to him one day for medical 
 treatment, whereupon he asked him the particulars about the 
 discovery of the skull, which he then forthefirst time learned. 
 This, therefore, makes it possible that while Mr. Mattison 
 found a skull as he asserts he did and gave it to Mr. Scribner 
 the wrong one was selected from Dr. Jones' pile, so that nothing 
 is known now of the nature of the true skull or of the incrusta- 
 tion upon it. But that Mr. Scribner or Dr. Jones endeavored 
 to impose upon Professor Whitney, is not credible from the 
 known character of the men, and from their behavior in the 
 whole matter; while there would have been no motive for 
 any one to have imposed upon poor Mr. Mattison who was 
 spending his last cent in vain efforts to find gold. And cer- 
 tainly, he made no effort to profit from the alleged discovery. 
 It follows simply that we must drop out of the discussion 
 everjrthing that has been heretofore been said about the 
 character of the skull. With that absent the discovery 
 reported by Mr. Mattison becomes more easily credible than 
 it was before. 
 
 A discovery in Idaho strongly confirmatory of tnose on the 
 Pacific Coast is too important and interesting to be omitted. 
 
 In the autumn of 1889, Mr. Charles Francis Adams, then 
 President of the Union Pacific Railroad, brought to my notice 
 a small clay image, an inch and a half in length, which had 
 been found by Mr. M. A. Kurtz while boring an artesian well 
 at Nampa, Ada county, Idaho. The image was of slightly 
 baked clay, incrusted in part with a coating of red oxide of 
 
702 THE ICE AGE IN NORTH AMERICA. 
 
 iron, which indicated considerable age, and came up in the 
 sand-pump from a depth of three hundred and twenty feet. 
 Near the surface the well penetrated a stratum of basalt, fifteen 
 feet thick. Below this basalt there were alternate beds of clav 
 and quicksand to the depth mentioned, where the sandstone 
 rock was encountered. The well was tubed with heavy iron 
 tubing six inches in diameter, so that there could be no mistake 
 about the occurrence of the image at the depth stated. The 
 detailed evidence was published by me in the " Proceedings of 
 the Boston Society of Natural History " for January, 1890. 
 During the following summer, I visited the locality and found 
 ample confirmation of it. 
 
 It is proper also to be stated that Mr. G. M. Gumming, 
 general manager of the Union Pacific lines in that district was 
 on the ground the day the "find" was made, and carefully 
 scanned the evidence, with the conclusion that there was no 
 doubt of the facts as given. Probably no person in the world 
 was better able than he to judge of the evidence. Later, other 
 ofiicials of the railroad who had interests in the vicinity took 
 pains at my suggestion to re-examine the evidence with the 
 result of confirming it in every respect. On the other hand, 
 no one has come forward to challenge the evidence except on 
 purely d priori grounds arising from preconceived opinions 
 of the extreme antiquity of the deposits in which it is said 
 to have been found. Close attention to the accompanying 
 conditions will, however, I think modify these preconceptions. 
 
 In the valley between the Boise and Snake Rivers, in south- 
 western Idaho, where Nampa is situated, there is an area of sev- 
 eral hundred square miles covered with fresh-appearing basalt, 
 which apparently came from vents thirty or forty miles to the 
 east, but in its western ilow barely extended five miles beyond 
 Nampa. Below that point there is no lava for seventy miles. 
 The clay and quicksand covering the stratum in which the 
 image was found would seem to have accumulated in the valley 
 of a stream having access to such an amount of sedimentary 
 material that for a time it filled up rather than eroded its chan- 
 nel. Apparently the conditions favorable for such effects would 
 
MAN AND THE LAVA BEDS. 
 
 703 
 
 be most readily furnish during the Glacial period, when the 
 streams of that region were swollen not only with the in- 
 creased annual precipation, but with the melting of the 
 glaciers which doubtless had for a long time occupied the 
 mountains near the head-waters of the Bois6 River to the 
 north. Very likely, also, the lava-flows which obstructed 
 the river a few miles above Bois6 City turned its course to 
 the southward, so that it may have wandered for some time 
 over the plain in the vicinity of Nampa. 
 
 Fig. 196 — Nampa figurine 'and map 'of the Snake river valley Illustrating the text. 
 For photograph of the bowld&r bed at Pocatello described In the text, see page 615. 
 
 In addition to these general considerations we have here 
 a most interesting and suggestive special situation from which 
 much evidence may be derived in support of the foregoing 
 interpretation of the facts. In the summer of 1890, while 
 making investigations in the Snake River Valley at Pocatello, 
 350 miles above Nampa, and where the elevation is 2000 feet 
 higher, I was confronted with an immense delta of bowlders, 
 many of them three and four feet in diameter, at a consider- 
 able distance from the foot hills of the mountains to the south , 
 which seemed inexplicable from any natural causes within 
 
704 THE ICE AGE IN NORTH AMERICA. 
 
 my knowledge. This delta of bowlders had been covered with 
 a thin deposit of loam, and the city of Pocatello was built 
 upon it. While I was there the city authorities were endeavor- 
 ing to put in a sewer system, but were impeded by the general 
 occurrence of these obstructing bowlders of great size. This 
 bowlder bed is just where the Port Neuf River debouches 
 upon the Snake River Plain. But upon going up the tributary 
 valley a half mile or so the large bowlders ceased, and there 
 was a scoured out channel free from them. 
 
 The explanation of this puzzling phenomenon was soon 
 found in the result of Mr. Gilbert's investigations respecting 
 the history of Lake Bonneville, to which reference has already 
 been made. It was through the Port Neuf River that the 
 great debacle from Lake Bonneville poured when the rising 
 water surmounted the 1000-foot dirt barrier which retained 
 the upper 350 feet of water over an area of 20,000 square 
 miles. Mr. Gilbert estimates that it would require twenty 
 years for a stream as large as Niagara to lower this body 
 of water to the bottom of the dirt dam which was finally 
 broken through, and that a stream as large as that did mean- 
 while pour through the opening leading to the Port Neuf, 
 and so on into the Snake River Valley at Pocatello. Here, 
 therefore, we have not only an adequate cause for the bowlder 
 bed at Pocatello with all its peculiarities, but for the seeniingly 
 anomalous facts in the valley at Nampa 350 miles below, and 
 at a level 2000 feet nearer that of the sea. The conditibiis 
 were such as to favor the rapid accumulation of fine sediment 
 which appears above the mouth of Bois6 River, and above the 
 great constriction of the channel which occurs a short distance 
 beyond at Huntington, and continues for a long distance 
 below. 
 
 , 1 . ' , 
 
 Light is shed upon the geological date of this debacle by 
 the fossils found at Glens Ferry, about half way betweefi Pb- 
 catello and Nampa, and described by Dr. Dall. They are as 
 follows: Goniobasis taylori Gabb (sp.), Lithasia antiqua Gabb, 
 
MAN AND THE LAVA BEDS. 705 
 
 LaiiaddlH White, SphoeriumidahoensisMeek, a,ndS. negosutn 
 Meekl . 
 
 These are found in consolidated gravel 100 feet beneath 
 a thick capping of lava. The elevation of the lava here is 
 400 feet above that at Nampa, 85 miles farther down the 
 rivier. According to Dall these sedimentary rocks belong to 
 Cope's "Idaho Lake," and are "very likely middle or later 
 pliocene. Both the unconsolidated character of the Nampa 
 beds and the lower level at which they occur indicate a pleisto- 
 cene age. They occur in a basin which has either been eroded 
 out of Pliocene deposits synchronous with those at Glens 
 Ferry, or in one formed by uneven elevations of land of which 
 we have no definite record. The rapidity with which the 
 deposits at Nampa were formed appears from their character. 
 One of the beds of quicksand was 100 feet thick and two other 
 40 and 30 respectively. For 70 miles below Nampa there are 
 no superficial lava beds, while there at the Oregon line, the 
 Snake River Valley becomes very much constricted, and con- 
 tinues in a narrow gorge for a long distance. The situation 
 furnishes just such conditions as would favor the rapid 
 accumulation of fine sediment naturally brought down by 
 such debacle from Lake Bonneville as is known to have taken 
 place in pleistocene or glacial times. With respect to the 
 age of the lava deposits it is also to be said that all observers, 
 (especially Hayden and Russell) call frequent attention to 
 outflow^s of lava in various parts of the Snake River Valley 
 that are very recent — some of them not more than two or 
 three centuries old. We, therefore, are amply justified in 
 connecting the Nampa figurine with deposits of glacial age. 
 
706 THE ICE AGE IN NORTH AMERICA. 
 
 Conclusion. In the discoveries narrated above of man's 
 relation to the glacial epoch the study of every class of glacial 
 phenomena becomes invested with all the higher interest of 
 historical research. Signal changes were introduced into the 
 world's history by the conditions which accompanied the 
 Glacial epoch. In America as well as in Europe this advent 
 of northern cold greatly disturbed the conditions of animal 
 life, and, we may well suppose, directly led to the extinc- 
 tion of many animal species. In North America the camel, 
 the hippopotamus, the rhinoceros, the tapir, the mammoth, 
 the horse, the mastodon, were abundant at the opening of 
 the Quaternary age. Their complete extermination is one 
 of the most startling facts in geology. But, as Darwin has 
 so well shown, the effects of a glacial advance are by no 
 means limited to the region directly reached by the ice. In 
 pushing southward the plants and animals of the northern 
 part of the continent, the struggle for life in the more 
 crowded quarters of the decreasing congenial portions of the 
 country became more and more intense, and thus doubtless 
 was brought about much of the extinction of species which 
 the geologists have to record as having taken place in the 
 early part of the Quaternary period. The evidences of 
 man's existence in Iforth America before the close of the 
 Glacial period would indicate that he too shared in the sharp 
 struggle which ensued with the new and rapidly changing 
 conditions of that time. Did he also, hke so many of his 
 companions among the larger animals, share in this extinc- 
 tion ? The sharpness of the transition from the palaeolithic 
 to the neolithic type of implements, as we pass out from the 
 Trenton gravel into the shallow soil above it, would seem to 
 indicate an absolute distinction between the two succeeding 
 races. But even so, whether the first became extinct from 
 natural causes, and the other simply came in later as colonist, 
 or whether the latter as conqueror exterminated the first, 
 may always remain a doubtful question. It is possible that 
 the Eskimo is the lineal descendant of preglacial man in 
 America, and the conditions of life with which the Eskimo 
 
MAN AND THE LAVA BEDS. 707 
 
 is so passionately in love would seem to resemble closely 
 those which evidently surrounded palaeolithic man in Ifew 
 Jersey, Ohio, Indiana, and Minnesota. But, on the other 
 hand, such human remains as we have from the Trenton 
 gravel are regarded by Professor Putnam as belonging to a 
 race distinct in type from the Eskimo. 
 
 A closing remark is in place with reference to the date 
 of man's appearance in America. In the first place it should 
 be observed that, to say man was here before the close of 
 the Glacial period only fixes a minimum point as to his an- 
 tiquity. How long he may have been here previous to that 
 time must be determined by other considerations. Secondly, 
 with our present knowledge of glacial phenomena, the date 
 of the close of the Glacial period is regarded as much more 
 modern than it was a few years ago. Sir Charles Lyell's 
 estimate of thirty-five thousand years as the age of the Niag- 
 ara gorge, which is one of the best measures of post-glacial 
 time which has yet been studied, is greatly reduced by what 
 we now know of the rate at which erosion is proceeding at 
 the falls. Ten thousand years is now regarded as a liberal 
 allowance for the age of that gorge. But, finally, the term 
 " close of the Glacial period " is itself a very indefinite ex- 
 pression. The Glacial period was a great while in closing. 
 The erosion of the N"iagara gorge began at a time long sub- 
 sequent to the deposit of the gravel at Trenton and at Madi- 
 sonville. Between those two events time enough must have 
 elapsed for the ice-front to have receded a hundred miles or 
 more, or all the distance from New Tork to Albany ; since 
 only at that stage of retreat would the valley of the Mohawk 
 have been freed from ice so as to allow the Niagara River to 
 begin its work. The deposits at Trenton, Madisonville, and 
 Medora, took place while the ice-sheet still lingered in the 
 southern water-shed of New York and Ohio. When, there- 
 fore, the age of the mound-builders of Ohio is reckoned by 
 centuries, that of the glacial man who chipped these palaeo- 
 lithic implements must be reckoned by thousands of years. 
 
 As is evident from the description of Mr. Upham, the 
 
708 THE ICE AOE IN NORTH AMERICA. 
 
 gravel at Little Falls, Minn., is considerably more recent than 
 that in the more southern localities, since the gravel in Min- 
 nesota could have been deposited only when the ice-front had 
 retreated some hundreds of miles from its farthest extension, 
 while the first-named deposits occur near the very margin of 
 the glaciated area. 
 
 Most of those who have taken pains to read the preceding 
 pages through from the beginning have doubtless been sur- 
 prised at the wide range of questions involved in the subject 
 under discussion. The movement of ice itself brings up for 
 consideration one of the most singular and obscure of physical 
 problems. A wide field of investigation is still open to the 
 physicist in determining how it is that brittleness and mo- 
 bility can so unite in one substance as to produce the phe- 
 nomena of motion observed in living glaciers. The majesty 
 of the ice-movement, as brought to light in the study of the 
 glaciated area in Iforth America, is equaled only in the 
 movement of the forces of astronomy, or in that of those 
 which have elevated the mountain-ranges on the surface of 
 the earth. Almost every human interest in the northern 
 part of the United States and in British America is likewise 
 seen to be profoundly affected by the ice-movement which 
 we have been permitted to study. During the great Ice age 
 the old lines of drainage were obliterated, and new lines 
 established, crooked places were made straight, and rough 
 places plain. The change in the river-courses produced by 
 the obstruction of glacial deposits has given rise to the innu- 
 merable waterfalls where have grown up the flourishing 
 manufacturing and commercial centers of New England and 
 the interior. The Great Lakes are in the main the result of 
 similar glacial obstruction. The vast internal commerce of 
 the lake region avails itself of slack-water navigation result- 
 ing from the ice-movements of the Glacial age. The innu- 
 merable lakes of smaller size which adorn the surface of the 
 northern part of the continent are also the result of glacial 
 action. The anomalous distribution of insects and plants can 
 likewise, in many cases, be traced to the same cause. The 
 
MAN AND THE LAVA BEDS. 709 
 
 arctic batterflies and the Alpine flowers upon the summit of 
 Mount "Washington, as well as the gigantic forests of Califor- 
 nia and some of their more distant relatives on the Atlantic 
 coast, were fugitives from the arctic regions in glacial times, 
 who have since become naturalized citizens of the lower lati- 
 tudes. And, finally, man himself is connected with the clos- 
 ing centuries of the Glacial period in the United States. 
 American scholars who are ambitious to cany on archaeo- 
 logical investigations need no longer go to the valley of the 
 Euphrates or the Nile, or to the languages of central Asia, 
 to find the oldest relics of man in the world, or the surest 
 means of determining the greatness of his antiquity. A 
 boundless, comparatively unworked, most promising and most 
 interesting field lies before the American investigator in the 
 glacial problems of his own country. Nowhere else in the 
 world did the ice of the Glacial period deploy out upon so 
 wide a margin of dry land, and leave so inviting and easy a 
 field of study. Every river rising within the glacial boundary 
 and emerging from the glaciated region presents a problem 
 worthy of the life-long attention of any investigator. Every 
 glacial waterfall and every glacial lake holds out the possibil- 
 ity of yielding up an important clew to chronological ques- 
 tions of absorbing interest. The ingenuity of Professor Asa 
 Gray and others in tracing out the effects of the great Ice 
 age upon the distribution of plants and animals, has only 
 introduced us to subjects which need yet to be worked out 
 in endless detail. The object of the present treatise will be 
 largely accomplished if it serves to stimulate and guide the 
 host of local investigators which the subject is sure to in- 
 terest. 
 
BIBLIOGRAPHY 
 
 W. R. Abercrombie: "Crossing the Valdez Glacier, Alaska, at Bates 
 Bay," "American Geologist," vol. xxiv, pp. 349-354. 
 
 W. C. Alden: "The Chicago Folio," "Geol. Atlas of the United 
 States," U. S. Geological Survey, Folio 81; "Delevan Lobe of the 
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 Ralph Arnold: "The Tertiary and Quaternary Pectens of Califor- 
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 W. W. Atwood: "Glaciation of San Francisco Mountain, Arizona," 
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 H. Foster Bain: "Preglacial Elevation of Iowa," "Proceedings, 
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 near Sioux City, Iowa," ibid., pp. 20-23; "The Aftonian and Pre-Kan- 
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 on the Drift of Northwestern Iowa," "American Geologist, "vol. xxiii, 
 pp. 168-176; "Relation of the Wisconsin and Kansas Drift Sheets in 
 Central Iowa, and Related Phenomena," "Iowa Geological Survey," 
 vol. vi, pp. 433-476. 
 
 E. S. Batch: "Glaciers or Freezing Caverns," Phila., Allen, Lane 
 & Scott, 1900. 
 
 S. P. Baldwin: "Recent Changes in Muir Glacier," "American 
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 Valley," ibid., March, 1894. 
 
 H. M. Bannister: "The Drift and Geologic Time," "Journal of 
 Geology," vol. v, pp. 730-743. 
 
 E. H. Barbour: "Ancient Inhabitants of Nebraska," "Records of 
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 vol. ii, pt. 5, pp. 318-327, pt. 6, pp. 331-348, "Glacial Grooves and 
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 viii, pp. 309-312. 
 
712 THE ICE AGE IN NORTH AMERICA. 
 
 G. H. Barton: "Glacial Origin of Channels on Drumlins," "Bulle- 
 tin of the Geological Society of America," vol. vi, pp. 8-12; "Glacial 
 Observations in the Umanak District, Greenland," "Technological 
 Quarteriy," vol. x, pp. 213-244. 
 
 H. Basedow and J. D. Iliff: "On a Formation known as 'Glacial 
 Beds of Cambrian Age' in South Australia," " Quarteriy Journal of 
 the Geological Society of London," vol. Ixiv, pp. 260-263. 
 
 H. Bashore: "The Harrisburg Terraces," "American Journal of 
 Science," February, 1894; "Notes on Glacial Gravels in the Lower 
 Susquehanna Valley," ibid., April, 1896. 
 
 E. S. Bastin: "A Permian Glacial Invasion (in the Transvaal)," 
 "American Geologist," vol. xxix, pp. 169-170. 
 
 C. S. Beachler: "An Abandoned Pleistocene River Channel" 
 [in Decatur County, Ind.], "Journal of Geology," vol. ii, pp. 62-65. 
 
 J.M.Bell: "Douglass Glacier and its Neighborhood," "Geograph- 
 ical Journal," August, 1908; "Heart of the Southern Alps, New 
 Zealand," ibid., August, 1907. 
 
 Robert Bell: "Proofs of the Rising of the Land around Hudson Bay,'' 
 "American Journal of Science," March, 1896; "On Glacial Phenomena 
 in Canada," "Bulletin of the Geological Society of America," vol. 
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 Labrador Peninsula," "Scottish Geograpliical Magazine," July, 1895. 
 "The Geological History of Lake Superior," "Can. Inst. Trans.," 
 vol. vi, pp. '45-60. 
 
 C. P. Berkey: "Laminated Interglacial Clays of Grantsburg, Wis.," 
 "Journal, of Geology," vol. xiii, pp. 35-44. 
 
 S. W. Beyer: "Buried Loess in Story County [Iowa]," "Pro- 
 ceedings of the Iowa Academy of Science," vol. vi, pp. 117-121 ; " Evi- 
 dence of a Sub-Aftonian Till Sheet in Northeastern Iowa," ibid., 
 vol. iv, pp. 58-62. 
 
 Eliot Blackwelder: "Glacial Features of the Alaskan Coast between 
 Yakutat Bay and the Alsek River," "Journal of Geology," vol. xv, 
 pp. 415-433; "On the Probable Glacial Origin of Certain Folded 
 Slates in Southern Alaska," ibid., vol. xv, pp. 11-14. 
 
 W. P. Blake: "Glacial Erosion and the Origin of the Yosemite 
 Valley," "Transactions of the American Institute of Mining Engi- 
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 Quaternary of Arizona," "American Geologist," vol. xxii, pp. 65-72. 
 
 W. S. Blatchley: "Gold and Diamonds in Indiana," "Indiana 
 Department of Geology and Natural Resources," 27th Annual Report, 
 pp. 11-47. 
 
 /. A. Bovmocker: "History of the Little Miami River [Ohio]," 
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 J. H. Bretz: "Glacial Lakes of Puget Sound," "Journal of 
 Geology," vol. xviii, pp. 448-458. 
 
BIBLIOGRAPHY. 713 
 
 A. P. Brigham: " Drift Bowlders between the Mohawk and Susque- 
 hanna Rivers," "American Journal of Science," March, 1895; "The 
 Finger Lakes of New York," " Bulletin of the American Geographical 
 Society," 1893; "Rivers and the Evolution of Geographic Forms," 
 ibid., 1892; "A Chapter in Glacial History, with Illustrative Notes 
 from Central New York," "Transactioiis of the Oneida Historical 
 Society," 1892; "Glacial Flood Deposits in Chenango Valley" 
 [New York], "Bulletin of the Geological Society of America," vol. viii, 
 pp. 17-30; "Topography and Glacial Deposits of Mohawk Valley," 
 ibid., vol. ix, pp. 183-210. 
 
 R. W. Brock: "Boundary Creek District, British Columbia," 
 "Canada Geological Survey," Simunary Rept., 1901, pp. 49-67, 
 [Glaciation, p. 57]. 
 
 A. H. Brooks: "Sketch of the Geology of Southeastern Alaska," 
 "U. S. Geological Survey, Professional Paper," no. 1, pp. 31-33; 
 and others: "Reconnaissances in the Cape Nome and Norton Bay 
 Regions, Alaska, in 1900," "U. S. 56th Congress, 2d Sess., House 
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 E. R. Buckley: " Ice Ramparts," "Wis. Acad. Sci. Arts and Letters," 
 Trans., vol. xiii, pt. 1, pp. 141-157. 
 
 E. P. Buffett: "Some Glacial Conditions and Recent Changes on 
 Long Island," "Journal of Geography," February, 1903. 
 
 E. M. Burwash: " Geology of the Nipissing-Algonia Line [Ontario]," 
 "Ontario Bureau of Mines," 6th An. Bept., pp. 167-184. 
 
 F. H. H. Calhoun: "The Montana Lobe of the Keewatin Ice Sheet, ' ' 
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 Samitel Calvin: "The Buchanan Gravels: An Inter'glacial Deposit 
 in Buchanan County, Iowa," "American Geologist," February, 
 1896; "Geology of Jones County," "Iowa Geological Survey," vol. 
 V, (Annual Report, 1895), pp. 33-112; "The Aftonian Gravels and 
 their Relations to the Drift Sheets in the Region about Afton Junc- 
 tion and Thayer [Iowa]," "Proceedings of the Davenport Academy 
 of Sciences," vol. x, pp. 18-31; "lowan Drift," "Bulletin of the Geo- 
 logical Society of America," vol. x, pp. 107-120; "A Notable Ride 
 from Driftless Area to lowan Drift," "American Geologist," vol. 
 xxiv, pp. 372-376; "Present Phase of the Pleistocene Problem in 
 Iowa," "Bulletin of the Geological Society of America," vol. xx, 
 pp. 133-152. 
 
 FrankCarney: " Glacial Erosionin Longitudinal Valleys," "Journal 
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 can Journal of Science," March, 1908; " Pre-Wisconsin Drift in the 
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 pp. 671-585; "A Type Case in Diversion of Drainage," "Journal of 
 Geography," March, 1903; "Valley Dependencies of the Scioto 
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714 THE ICE AGE IN NORTH AMERICA. 
 
 vol. XV, pp. 488-495; "Wave-cut Terraces in Kueka Valley, Older 
 than the Recession Stage of Wisconsin Ice," "American Journal of 
 Science," May, 1907. 
 
 Austin Cory: "Geological Facts noted on Grand River, Labrador," 
 "American Journal of Science," November, 1891. 
 
 E. C. Case: "Experiments. in Ice Motion," "Journal of Geology," 
 vol. iii, pp. 918-934. 
 
 R. Chalmers: "Glacial Lake St. Lawrence of Professor Warren 
 Upham," "American Journal of Science," April, 1895; "Pleistocene 
 Marine Shore Lines on Southern Side of the St. Lawrence Valley," 
 ibid., April, 1896; "Height of the Bay of Fundy Coast in the Glacial 
 Period relative to Sea-Level, as evidenced by Marine Fossils in the 
 Bowlder-clay at St. John, N. B.," "Bulletin of the Geological Society 
 of America," vol. iv, pp. 361-370; "Geomorphic Origin and Develop- 
 ment of the Raised Shore Lines of the St. Lawrence Valley and Great 
 Lakes," "American Journal of Science," September, 1904; "The Glaci- 
 ation of Mount Orford, P. Q." [Canada], "Ottawa Naturalist," vol.xix, 
 pp. 62-55; "Preglacial Decay of Rocks in Eastern Canada," "Ameri- 
 can Journal of Science," April, 1898. 
 
 R. T. Chamberlin: "The Glacial Features of the St. Croix Dalles 
 Region," "Journal of Geology," vol. xiii, pp. 238-256. 
 
 T. C. Chamberlin: "On the Relationship of the Pleistocene to the 
 Pre-pleistocene Formation of the Mississippi Basin South of the Limit 
 of Glaciation," "American Journal of Science," May, 1891; "The 
 Diversity of the Glacial Period," ibid., March, 1893; "Further 
 Studies of the Drainage Features of the Upper Ohio Basin," ibid., 
 April, 1894; "Some Additional Evidences bearing on the Interval 
 between the Glacial Epochs," "Bulletin of the Geological Society of 
 America," vol. i, pp. 469-480; "Recent Glacial Studiesin Greenland," 
 ibid., vol. vi, pp. 199-220; "The Nature of the Englacial Drift of the 
 Mississippi Basin," "Journal of Geology," vol. i, pp. 47-60; "The 
 Horizon of Drumlin, Osar, and Kame Formation," ibid., pp. 255-267; 
 "Glacial Studies in Greenland," ibid., vol. ii, pp. 649-666, 768-788; 
 vol. iii, pp. 61-69, 198-218, 469-480, 565-582, 668-681, 833-843; "The 
 Classification of American Glacial Deposits," ibid., vol. iii, pp. 
 270-277; review of Wright's "New Evidence on Glacial Man in Ohio," 
 ibid., vol. iv, pp. 107, 219-221; "An Attempt to Frame a Working 
 Hypothesis of the Cause of Glacial Periods on an Atmospheric Basis," 
 ibid., vol. vii, pp. 545-584, 667-685, 761-787; "A Contribution to the 
 Theory of Glacial Motion," Decennial Publications of University of 
 Chicago," 1st ser., vol. ix, pp. 193-206; "The Geologic Relationsof 
 the Human Relics of Lansing, Kansas," "Journal of Geology," voL 
 X, pp. 745-779; "Glacial Studies in Greenland," "Journal of Geology," 
 vol. V, pp. 229-240; " Supplementary Hypothesis respecting the Ori- 
 gin of the Loess of the Mississippi Valley," "Journal of Geology," 
 vol. V, pp. 795-802. 
 
BIBLIOGRAPHY. 715 
 
 L. W. Chaney: "Glacier on Montana Rockies," "Science," Decem- 
 ber 13, 1895; " Glacial Exploration in the Montana Rockies," " Inter- 
 national Geographical Congress, 8th Report," pp. 403-496. 
 
 F. O. Clapp: "Geological History of the Charles River," [Massa- 
 chusetts], "Technology Quarterly," vol. xiv, pp. 171-201; "Relations 
 of Gravel Deposits in the Northern Part of Glacial Lake Charles, 
 Massachusetts," "Journal of Geology," vol. xii, pp. 198-214. 
 
 W. Blair Clark: "Drainage Modifications in Knox, Licking and 
 Coshocton Counties" [Ohio], "Bulletin of the Scientific Laboratories 
 of Denison University," vol. xii, pp. 1-16. 
 
 E. W. Claypole: "Glacial Notes from the Planet Mars," "American 
 Geologist," August, 1895; "Professor G. F. Wright and his Critics," 
 "Popular Science Monthly," April, 1893; "Glacial Theories— Cos- 
 mical and Terrestrial," "American Geologist," vol. xxii, pp. 310-315. 
 
 A. P. Coleman: " Interglacial Fossils from the Don Valley, Toronto," 
 "American Geologist," February, 1894; "Glacial and Interglacial 
 Deposits near Toronto," "Journal of Geology," vol. iii, pp. 622-645; 
 "Duration of the Toronto Interglacial Period," "American Geolo- 
 gist," vol. xxix, pp. 71-79; "Glacial and Interglacial Beds near 
 Toronto," "Journal of Geology," vol. ix, pp. 285-310. "Glacial and 
 Interglacial Deposits at Toronto [Canada]," "British Association 
 for the Advancement of Science," Report, 1897, pp. 650-651 ; " Glacial 
 Lakes and Pleistocene Changes in the St. Lawrence Valley," "Inter- 
 national Geographical Congress," 8th Report, pp. 480-486; "Glacial 
 Periods and their Bearing on Geological Theories," "Bulletin of the 
 Geological Society of America," vol. xix, pp. 347-366; "Lake Iro- 
 quois and its Predecessors at Toronto," ibid., vol. x, pp. 165-176; 
 "Lower Huronian Ice Age," "American Journal of Science," March, 
 1907; "The Lower Huronian Ice Age," "Journal of Geology," vol. 
 xvi, pp. 149-158; "On the Pleistocene near Toronto [Canada]," 
 "British Association for the Advancement of Science," Report, 1900, 
 pp. 328-334; "Relation of Changes of Levels to Interglacial Periods, 
 "Geological Magazine," Dec. 4, vol. ix, pp. 69-62. 
 
 G. H. Colton: "A Possible Cause of Osars," "Ohio Naturalist,'' 
 vol. ii, pp. 257. 
 
 F. M. Comstock: "A Small Esker in Western New York," "Ameri- 
 can Geologist," vol. xxxii, pp. 12-13. 
 
 W. M. Conway: "An Exploration in 1897 of some of the Glaciers of 
 Spitsbergen," "Geographical Journal," August, 1898. 
 
 W. O. Crosby: "Distribution and Probable Age of the Fossil 
 Shells in the Drumlins of the Boston Basin," "American Journal of 
 Science," December, 1894; "Englacial Drift," "American Geologist," 
 April, 1896; " Composition of Till or Boulder Clay, " " Proceedings of 
 the Boston Society of Natural History," vol. xxv, pp. 115-140; " Geo- 
 logical History of the Nashua Valley, N. H., during the Tertiary and 
 Quaternary Periods," "Technology Quarterly," vol. xii, pp. 288-324, 
 
716 THE ICE AGE IN NORTH AMERICA. 
 
 "Origin of Eskers," "American Geologist," vol. xxx,pp. l-39;"Struc- 
 ture and Composition of the Delta Plains formed during the Clinton 
 Stage in the Glacial Lake of the Nashua Valley," "Technology 
 Quarteriy," vol. xvi, pp. 240-254, vol. xvii, pp. 37-75. 
 
 F. Cross. "TheBuriedValleyof Wyoming [Pennsylvania]," "Wyom- 
 ing Hist, and Geol. Soc, Proc. and Coll., vol. viii, pp. 42-44. 
 
 G. E. Culver: "On a Little-Known Re^on of Northwestern Mon- 
 tana," "Transactions of the Wisconsin Academy of Science," vol. 
 viii, pp. 188-205; "The Erosive Action of Ice," ibid., vol. x, pp. 
 339-366. 
 
 P. W. Currie: "On the Ancient Drainage at Niagara Falls," "Can. 
 Inst., Trans.," vol. vii, pp. 7-14. 
 
 G. C. Curtis and J. B. Woodworth: "Nantucket a Morainal Island," 
 "Journal of Geology," vol. vii, pp. 226-236. 
 
 H. P. Cushing: " Notes on the Muir Glacier Region, Alaska, and its 
 Geology," "American Geologist," October, 1891. 
 
 R. A. Daley: "Geology of the Region Adjoining the Western Part 
 of the International Boundary," "Canada Geol. Survey," Summary 
 Rept., 1901, pp. 37-t9. [Glaciation, pp. 41-45]. 
 
 /. D. Dana: "On New England and the Upper Mississippi Basin 
 in the Glacial Period," "American Journal of Science," November, 
 1893; "Manual of Geology," fourth edition, 1895, pp. 943-995. 
 
 George Davidson: "The Glaciers of Alaska that are shown on Rus- 
 sian Charts or mentioned in Older Narratives," "Geog. Soc. of Pac, 
 Trans, and Proc," 2d. ser., vol. iii, pp. 1-98. 
 
 W. M. Davis: "Structure and Origin of Glacial Sand Plains," 
 ''Bulletin of the Geological Society of America," vol. i, pp. 195-202; 
 "Subglacial Origin of Certain Eskers," "Proceedings of the Boston 
 Society of Natural History," May 18, 1892; " Glacial Origin of Lakes," 
 "Science," June 14,1895; "Glacial Lakes of Western New York," ibid., 
 July 5, 1895; " Causes of Permo-Carboniferous Glaciation, "Journal 
 of Geology," vol. xvi, pp. 79-82; "Glacial Erosion in France, Switz- 
 erland, and Norway," "Proceedings, Boston Society of Natural 
 History," vol. xxix, pp. 273-322; "Glacial Erosion in the Valley of 
 the Ticino," "Appalachia," vol. ix, pp. 136-155; "Glacial Erosion in 
 the Sawatch Range, Colo.," ibid., vol. x. pp. 392-404; "Glaciation of 
 the Sawatch Range, Colorado," "Bulletin of the Museum of Com- 
 parative Zofilogy of Harvard College," vol. xlix, pp. 1-11; "River 
 Terraces in New England," ibid., vol. xxxviii, pp. 281-346; "Terraces 
 of the Westfield River, Mass.," "American Journal of Science," 
 August, 1902. 
 
 G. M. Dawson: "Glacial Deposits of Southwestern Alberta in the 
 Vicinity of the Rocky Mountains," "Bulletin of Geological Society 
 of America," vol. vii, pp. 31-66; "Notes on the Occurrence of Mam- 
 moth Remains in the Yukon District of Canada and in Alaska," 
 "Quarterly Journal of the Geological Society," "February, 1894; 
 
BIBLIOGRAPHY. Ill 
 
 "Notes on the Glacial Deposits of Southwestern Alberta," "Journal 
 of Geology," vol. iii, pp. 507-511 ; "Are the Bowlder Clays of the Great 
 Plains Marine?" "Journal of Geology," vol. v, pp. 257-262. 
 
 J. William Dawson: "On the Pleistocene Flora of Canada," 
 "Bulletin of the Geological Society of America," vol. i, pp. 311-334; 
 "Canadian Ice Age: Being Notes on the Pleistocene Geology of 
 Canada, with Especial Reference to the Life of the Period and its 
 Climatal Conditions," 1893. 
 
 W. L. Dawson: " Glacial Phenomena in Okanogan County, Washing- 
 ton," "American Geologist,'' vol. xxii, pp. 203-217. 
 
 G. De Geer: "On Pleistocene Changes of Level in Eastern North 
 America," "Proceedings of the Boston Society of Natural History," 
 May 18, 1892. 
 
 H. N. Dickson: "Mean Temperature of the Atmosphere and the 
 Causes of Glacial Periods," "Geographical Journal, "November, 1901. 
 
 /. S. Diller: "Glaciation of Mount Mazama," "U. S. Geol. Survey, 
 Professional Paper," No. iii, pp. 41-44. 
 
 D. B. Dowling: "Physical Geography of Red River Valley," 
 "Ottawa Naturalist," vol. xv, pp. 115-120: "West Shore and Islands 
 Lake Winnepeg," "Canada Geological Survey," An. Rept., vol. 
 xi, pp. 93-100. 
 
 P. Dresser: "Note on the Glaciation of Mount Orford, P. Q.," 
 "Canadian Record of Science," vol. viii, pp. 223-225. 
 
 J. A. Druskel, "Glacial Drift under the St. Louis Loess, "Journal 
 of Geology, vol. xvi, pp. 493-498. 
 
 C. R. Dryer: "Certain Peculiar Eskers and Esker Lakes of North- 
 eastern Indiana," "Journal of Geology," vol. ix, pp. 123-129; "Fin- 
 ger Lake Region of Western New York," "Bulletin of the Geological 
 Society of America," vol. xv, pp. 449-460. 
 
 R. L. Dunn: "The Country of the Klondike [Alaska]," "Mining and 
 Scientific Press," vol. Ixxvii, pp. 400, 425-426, 449. 
 
 J. W.Eggleston: "Glacial Remains near Woodstock, Connecticut," 
 "American Journal of Science," May, 1902. 
 
 A. H. Elftman: "Geology of the Keweenawan Area in Northeast- 
 em Minnesota," "American Geologist," vol. xxi, pp. 90-109; "The 
 St. Croix River Valley [Minnesota-Wisconsin]," ibid. vol. xxii, pp. 
 58-61. 
 
 R. W. Ells: "Ancient Channels of the Ottawa River" [Canada], 
 "Ottawa NaturaUst," vol. xv, pp. 17-30. 
 
 B. K. Emerson: "Geology of Old Hampshire County, Massachu- 
 setts, comprising, Franklin Hampshire, and Hampden Counties," 
 "United States Geological Survey," Monograph xxix. 
 
 P. M. Emerson: " Glacial Topography in Central New Hampshire, 
 "Appalachia," vol. x, pp. 299-303. 
 
 H. L. Fairchild: "The Kame Moraine at Rochester, N. Y.;" 
 "American Geologist," July, 1895; "Glacial Lakes of Western New 
 
718 THE ICE AGE IN NORTH AMERICA. 
 
 York," "Bulletin of the Geological Society of America," vol. vi, 
 pp. 353-374; "Lake Newberry the Probable Successor of Lake Warren," 
 ibid., pp. 462-466; "Kame Areas in Western New York South of Iron- 
 dequoit and Sodus Bays," "Journal of Geology," vol. iv, pp. 129- 
 159; "The Length of Geologic Time," "Proceedings of the Rochester 
 Academy of Science," April 23, 1894; "Glacial Geology of Western 
 New York," "Geological Magazine," Dec. 4, vol. iv, pp. 529-^37; 
 "Glacial Geology in America," "American Geologist," vol. xxii, 
 pp. 154^189; "Glacial Lakes Newberry, Warren and Dana, in Central 
 New York." "American Journal of Science," April, 1899; "Glacial 
 Waters from Oneida to Little Falls," "New York State Museum," 
 56th An. Rep., vol. 1 ; " Glacial Waters in the Finger Lakes Region of 
 New York," "Bulletin of the Geological Society of America," vol. 
 X, pp. 27-68; "Ice Erosion Theory a Fallacy," ibid., vol. xvi, pp. 13- 
 74; "Kettles in Glacial Lake Deltas," "Journal of Geology," vol. 
 vi, pp. 589-596; "Lake Warren Shorelines in Western New York and 
 the Geneva Beach," "Bulletin of the Geological Society of America," 
 vol. viii, pp. 269-284; "Latest and Lowest Pre-Iroquois Channels 
 between Syracuse and Rome," "New York State Museum," 55th An. 
 Rept., pp. r31-r47; "Pleistocene Features in the Syracuse Region," 
 "American Geologist," vol. xxxvi, pp. 135-141; "Pleistocene Geblogy 
 of Western New York," "20th Report of State Geologist," 1900, 
 pp. 103-139. 
 
 N. M. Fennerman: "The Arapahoe Glacier in 1902," "Journal of 
 Geology," vol. x, pp. 839-851. 
 
 H. G. Fergitson: "Tertiary and Recent Glaciation of an Icelandic 
 Valley," "Journal of Geology," vol. xiv, pp. 122-133. 
 
 G. E. Finch: "Drift Section at Oelwein, Iowa," "Iowa Acad. Sci. 
 Proceed.," vol. iv, pp. 54-58. 
 
 George Finlay: "GraniteAreaofBarre, Vermont," "An. Rept. State 
 Geologist," 1902, pp. 46-4S. 
 
 T. J. Fitzpatrick: "The Drift Section and the Glacial Striae in 
 the Vicinity of Lamoni," "lowaAcad. Sci. Proc," vol. v, pp. 105-106. 
 
 Gerard Fowke: "Preglacial Drainage Conditions in the Vicinity of 
 Cincinnati)" "Ohio State Academy of Science," Special Papers, No. 
 iii, pp. 68-75; "Pre-Glacial Drainage in the Vicinity of Cincinnati, 
 its Relation to the Origin of the Modern Ohio River, and its Bearing 
 upon the Question of the Southern Limits of the Ice Sheet," "Bulle- 
 tin of the Scientific Laboratories of Denison University," vol. xi, 
 pp. 1-10. "The Preglacial Drainage of Ohio — Introduction," "Ohio 
 State Academy of Sciences," Special Papers, no. iii. pp. 5-9. 
 
 C. D. Fox: "The Glaciers, Past and Present, in the South Island 
 of New Zealand," "Journal of Transactions of the Victoria Institute," 
 vol. xl. 
 
 I). W. Freshfield: "Glaciers of Kangchenjunga," "Geographical 
 Journal," April, 1902. 
 
BIBLIOGRAPHY. 719 
 
 M. L. Fuller: "Champlain Submergence in the Narraganset Bay- 
 Region," "American Geologist," vol. xxi, pp. 310-321; "General and 
 Pleistocene Geology of the Ditney, Indiana Folio,'' "Geological 
 Atlas of the United States," "U. S. Geol. Survey" Folio, no. 84, p, 
 1-7; "Geology of Fishers Island, New York," "Bulletin of the Geo- 
 logical Society of America," vol. xvi, pp. 367-390; "Ice-Retreat in 
 Glacial Lake Neponset and in Southeastern Massachusetts," "Jour- 
 nal of Geology," vol. xii, pp. 181-197; "Probable Pre-Kansan and 
 lowan Deposits on Long Island," "American Geologist," vol. xxxii, 
 pp. 308-311; "Probable Representatives of Pre-Wisconsin Till in 
 Southeastern Massachusetts," "Journal of Geology," vol. ix, pp. 
 311-329; "Season and Time Elements in Sand-plain Formation," 
 ibid., vol. vii, pp. 452-462. 
 
 A. Fullon: Results of Glacial Action in Canada," "Technical 
 World," vol. viii, 144-150. 
 
 F. M. Full?.: "Glacial Markings in Southeastern Iowa," "Proceed- 
 ings of the Iowa Academy of Science, 1894;" "Extension of the Illi- 
 nois Lobe of the Great Ice Sheet into Iowa," ibid.; "Glacial Scorings 
 in Des Moines County, Iowa," "Second Annual Report of Iowa Geo- 
 logical Survey," vol. iii, pp. 158-163; "Glaciers of America," "School 
 and Home Education," vol. xxvii, pp. 169-177. 
 
 Henry Gannett: "Lake Chelan and its Glacier [Washington]," 
 "Mazama," vol. ii, pp. 185-189. 
 
 V. H. Gatty: "Glacial Aspect of Ben Nevis," "Geographical Jour- 
 nal," May, 1906. 
 
 James Geikie: "The Classification of European Glacial Deposits," 
 "Journal of Geology," vol. iii, pp. 241-269; "The Last Great Baltic 
 Glacier," ibid., vol. v, pp. 325-339; "On the So-called 'Postglacial 
 Formations' of Scotland," ibid, vol. xiv, pp. 668-682. 
 
 G. K. Gilbert: "Lake Basins created by Wind Erosion," "Journal 
 of Geology," vol. iii, pp. 47-49; "Alaska, Glaciers and Glaciation," 
 "Harriman Alaska Expedition," vol. iii; "Bowlder-Pavement at Wil- 
 son, N. Y.," "Journal of Geology," vol. vi, pp. 771-775; "Crescentic 
 Gouges on Glaciated Surfaces," "Bulletin of the Geological Society 
 of America," vol. xvii, pp. 303-316; "Glacial Sculpture in Western 
 New York, "ibid., vol. x, pp. 121-130; "Moulin Work under Glaciers," 
 ibid., vol. xvii, pp. 317-320; "Rate of Recession of Niagara Falls," 
 accompanied by a report on the survey of the crest by W. C. Hall, 
 "Bulletin of the United States Geological Survey," No. 306; "Recent 
 Earth Movements in the Great Lakes Region," "United States Geo- 
 logical Survey," 18th An. Report, pt. iii, pp. 595-647; "Summary 
 History of Niagara Falls," "American Geologist, vol. xxvii, pp. 375- 
 377; "Variations of Sierra Glaciers," "Sierra Club Bulletin," vol. v, 
 pp. 20-25. "Glaciers of Alaska" [Review of G. K Gilbert's "Alaska; 
 Glaciers and Glaciation"], "National Geographic Magazine," No- 
 vember. 1904. 
 
720 THE ICE AGE IN NORTH AMERICA. 
 
 J.W.Goldthwait: " Isobases of the Algonquin and Iroquois Beaches 
 and their Significance," "Bulletin of the Geological Society ot Amer- 
 ica," vol. xxi, pp. 227-248; "A Reconstruction of Water Planes of 
 the Extinct Glacial Lakes in the Lake Michigan Basin," "Journal of 
 Geology," vol. xvi, pp. 459-476; "The Sand Plains of Glacial Lake 
 Sudbury," "Bulletin of the Museum of Comparative Zoology of Har- 
 vard College," vol. xiii, pp. 263-301. 
 
 C. H. Gordon: "Buried River Channels in Southeastern Iowa," 
 "Second Annual Report of the Iowa Geolo^cal Survey," vol. iii, 
 pp. 237-256; "Notes on the Kalamazoo and Other Old Glacial Out- 
 lets in Michigan," "Journal of Geology," vol. vi, pp. 477-482. 
 
 R. W. Gorman: "Ice Cliffs on White River, Yukon Territory," 
 "National Geographic Magazine," March, 1900. 
 
 A. W. Grabau: "The Preglacial Channel of the Genesee River," 
 "Proceedings of the Boston Society of Natural History," May 16, 
 1894; " Gviide to the Geology and Paleontology of Niagara Falls and 
 Vicinity," "Bulletinof the New York State Museum," No. 45, 284 pp.; 
 "Lake Bouv6, an Extinct Glacial Lake in the Southern Part of the 
 Boston Basin," "Occasional Papers, Boston Society of Natural His- 
 tory" IV, pt. iii, pp. 564^600. 
 
 U. S. Grant: " Lakes with two Outlets in Northeastern Minnesota," 
 "American Geologist," vol. xdx, pp. 407-411; "A Possible Driftless 
 Area in Northeastern Minnesota," ibid., vol. xxiv, pp. 377-381. 
 
 W. M. Gregory: "The Alabaster Area [Michigan]," "Michigan 
 Geological Survey," vol. ix, pt. 2, pp. 60-77. 
 
 W. Griffith: "An Investigation of the Buried Valley of Wyoming 
 [Pennsylvania]" "Proceedings and Collections of the Wyoming 
 Historical and Geological Society," vol. vi, pp. 27-36. 
 
 F. P. Gulliver: "The Newtonville [Mass.] Sand-Plain," "Journal 
 of Geology," vol. i, pp. 803-812. 
 
 Ossian Guthrie: "The Newly Discovered Moraines in Illinois: 
 Their Relations to the Glacial Channels across the Chicago Divide," 
 "Proceedings of the Chicago Geological Society," May 19, 1893. 
 
 J. C. Gwillim: "Glaciation in the Atlin District, British Columbia," 
 "Journal of Geology," vol. x, pp. 182-185. 
 
 F. W. Harmer: "Origin of Certain Canon -like Valleys associated 
 with Lake-like Areas of Depression," "Quarterly Journal of the Geo- 
 logical Soc. of London, vol. Ixiii, pp. 470-514. 
 
 T. W. Harris: "The Kames of the Oriskany Valley [N. Y.]," 
 "American Geologist," June, 1894. 
 
 C. W. Hayes and A. H. Brooks: "Ice Cliffs on White River, Yukon 
 Territory," "National Geographic Magazine," May, 1900. 
 
 A. Heilprin: "The Glaciers of Greenland," "Popular Science 
 Monthly," November, 1894. 
 
 Junius Henderson: "Arapahoe Glacier in 1903," "Journal of Geol- 
 ogy)'' vol. xii, pp. 30-33; "Arapahoe Glacier in 1905," ibid., vol. 
 
BIBLIOGRAPHY. 721 
 
 xiii,pp.556; "Extinct Glaciers of Colorado," " Studies of the Univer- 
 sity of Colorado," vol. iii, pp. 39-44. 
 
 0. H. Hershey: "The Pleistocene Rock Gorges of Northwestern 
 Illinois," "American Geologist," November, 1893; "The Columbia 
 Formation in Northwestern Illinois," ibid., January, 1895; "Age of 
 the Kansan Drift Sheet," ibid., vol. xxviii, pp. 20-25; "Ancient 
 Alpine Glaciers of the Sierra Costa Mountains in California," "Jour- 
 nal of Geology," vol. viii, pp. 42-57; "Certain River Terraces of the 
 Klamath Region, California," "American Journal of Science," Sep- 
 tember, 1903; "Eskers Indicating Stages of Glacial Recession in the 
 Kansan Epoch in Northern Illinois," "American Geologist," vol. 
 xix, pp. 197-209, 237-253; "The Inferior Boundary of the Quater- 
 nary Era," "American Naturalist," vol. xxxi, pp. 104-114; "The 
 Loess Formation of the Mississippi Valley," "Science," n. s. vol. 
 V, pp. 768-770; "Mode of Formation of Till as Illustrated by the 
 Kansan Drift of Northern Illinois," "Journal of Geology," vol. v, 
 pp. 50-62; "The Quaternary of Southern California," "Bulletin of 
 the Department of Geology of the University of California," vol. iii, 
 pp. 1-30; "Relation between Certain River Terraces and the Glacial 
 Series in Northwestern California," "Journal of Geology," vol. xi, 
 pp. 431-458; "The River Terraces of the Orleans Basin, California," 
 "Bulletin of the Department of Geology of the University of Cali- 
 fornia," vol. iii, pp. 423-475; "Some Evidence of Two Glacial Stages 
 in the Klamath Mountains in California," "American Geologist," 
 vol. xxxi, pp. 139-156; "The Upland Loess of Missouri — its Mode of 
 Formation," "American Geologist," vol. xxv, pp. 369-374. 
 
 B. R. Hice: "Glacial Grooves at the Southern Margin of the Drift," 
 "Bulletin of the Geological Society of America," vol. ii, pp. 457-464; 
 "The Inner Gorge Terraces of the Upper Ohio and Beaver Rivers," 
 "American Journal of Science," February, 1895; " Note on the Buried 
 Drainage System of the Upper Ohio," "Science," September 29, 
 1883; "The Clays of the Upper Ohio and Beaver River Region," 
 "Transactionsof American Ceramic Society, "vol. vii, pt. 2; "North- 
 ward Flow of Ancient Beaver River," "Bulletin of the Geological 
 Society of America," vol. xiv, pp. 297-304. 
 
 William Hill: "On a Deep Channel of Drift at Hitchin (Hertford- 
 shire)," "Quarterly Journal of the Geological Society of London," 
 vol. Ixiv, pp. 8-26. 
 
 C. H. Hitchcock: "Divisions of the Ice Age in the United States 
 and Canada," "American Geologist," May, 1895; "Glaciation of the 
 White Mountains, N. H.," "Bulletin of the Geological Society of 
 America," vol. v, pp. 35-37; "Terminal Moraines in New England," 
 "Proceedings of the A. A. A. S." vol. xli, pp. 173-175; "Champlain 
 Glacial Epoch," "Science," September 6, 1895; "Ancient Glacial 
 Action in Australasia," "American Geologist," vol. xxiii, pp. 252-257; 
 "Eastern Lobe of the Ice Sheet," ibid., vol. xx, pp. 27-33; "Glacia- 
 
722 THE ICE AGE IN NORTH AMERICA. 
 
 tion of the Green Mountain Range," " Vermont Geological Survey, 
 Report of the State Geologist," iv, pp. 67-85; "Glaciation of the Green 
 Mountains," Montpelier. Vt., Argus and Patriot Press 1904; "Inter- 
 glacial Deposits in the Connecticut Valley," "Bulletin of the Geo- 
 logical Society of America," vol. xii, pp. 9-10; "New Zealand in the 
 Ice Age," "American Geologist," vol. xxviii, pp. 271-281; "The Story 
 of Niagara," "American Antiquarian," vol. xxiii, pp. 1-24. 
 
 W. H. Hobbs: "Emigrant Diamonds in America," "Popular . 
 Science Monthly," vol. Ivi, pp. 73-83; " Instances of the Action of the 
 Ice-sheet upon Slender Projecting Rock Masses, " " American Journal 
 of Science," December, 1902. 
 
 T. H. Holland: "Observations of Glacier Movements in the Hima- 
 layas," "Geographical Journal," March, 1908. 
 
 Arthur Hollick: "A Reconnaissance of the Elisabeth Islands" 
 PVIassachusetts], "Annals of the New York Academy of Science," 
 vol. xiii, pp. 387-418. 
 
 W. H. Holmes: "Vestiges of Early Man in Minnesota," "American 
 Geologist," April, 1893; "Are there Traces of Glacial Man in the 
 Trenton Gravels?" "Journal of Geology," vol. i, pp. 15-163; "Traces 
 of Glacial Man in Ohio," ibid., vol. i, pp. 147-163-; "Fossil Human 
 Remains found near Lansing, Kansas," "American Anthropologist," 
 n. s. vol. iv, pp. 743-752. 
 
 T. C. Hopkins: "Glacial Climate," "Proceedings of the Onandaga 
 Academy of Science," vol. i, pp. 74-81. 
 
 Walter Howchin: "Glacial Beds of Cambrian Age in South Aus- 
 tralia," "Quarterly Journal of the Geological Society of London," 
 vol. Ixiv, pp. 234-263. 
 
 G. D. Hubbard: "Ancient Finger Lakes in Ohio," "American 
 Journal of Science," March, 1908; "High Level Terraces in South- 
 eastern Ohio," "American Journal of Science," February, 1908; 
 "An Interglacial Valley in Illinois," "Journal of Geology," vol. 
 xii, pp. 152-160; "On the Origin of Fiords," " Bulletin of the American 
 Geographical Society," vol. xxxiii, pp. 401-408. 
 
 E. Hull: "Another Possible Cause of the Glacial Epoch," "Journal 
 of Transactions of the Victoria Institute," vol. xxxi. 
 
 Ellsworth Huntington: "Pangong: a Glacial Lake in the Tibetan 
 Plateau," "Journal of Geology," vol. xiv, pp. 599-617; "Some Char- 
 acteristics of the Glacial Period in Non-Glaciated Regions, " " Bulletin 
 of the Geological Society of America," vol. xviii, pp. 351-388; 
 "Pulse of Asia," 1907. 
 
 /. E. Hyde: "Changes in the Drainage near Lancaster [Ohio]," 
 "Ohio Naturalist," vol. iv, pp. 149-157. 
 
 T. F. Jamieson: " Glacial Period in Aberdeenshire and the Southern 
 Border of the Moray Firth," "Quarterly Journal of the Geological 
 Society of London," vol. Ixii, pp. 13-39. 
 
 M. S. W. Jefferson: "The Postglacial Connecticut at Turners Falls, 
 Mass.," "Journal of Geology," vol. vi, pp. 463-472. 
 
BIBLIOGRAPHY 7'23 
 
 Mark Jefferson: "Glacial Erosion in the Northfiord," "Bulletin 
 of the Geological Society of America," vol. xviii, pp. 413-426; "Lateral 
 Erosion on Some Michigan Rivers," "Bulletin of the Geological 
 Society of America," vol. xviii, pp. 333-350. 
 
 B. C. Jillson: "River Terraces in and near Pittsburg," "Proceed- 
 ings of the Pittsburg Academy of Sciences and Arts," December 8, 
 1893. 
 
 H'. D. Johnsort: "Grade Profile in Alpine Glacial Erosion," "Sierra 
 Club Bulletin," vol. v, pp. 271-278; "The Profile of Maturity in 
 Alpine Glacial Erosion," "Journal of Geology," vol. xii, pp. 569-578. 
 
 F. O. Jones: "Glacial Rock Sliding," "Journal of Geology," vol. 
 XV, pp. 485-487. 
 
 A. A. Julien: "Geology of Central Cape Cod," "American Geol- 
 ogist," vol. xxvii, p. 44. 
 
 K. Keilhack: "Professor Geikie's Classification of the North Euro- 
 pean Glacial Deposits," "Journal of Geology," vol. v, pp. 113-125. 
 
 D. S. Kellogg: "Glacial Phenomena in Northeastern New York," 
 "Science," June, 17, 1892. 
 
 /. F. Kemp: "Buried Channels Beneath the Hudson and its Trib- 
 utaries," "American Journal of Science," October, 1908; "Geology 
 of the Lake Placid Region [New York]," "Bulletin of the New York 
 State Museum," vol. v, pp. 51-67; "The Glacial or Post-Glacial 
 Diversion of the Bronx River [New York] from its Old Channel," 
 "N. Y. Acad. Sci., Trans.," vol. xvi, pp. 18-24; "An Interesting Dis- 
 covery of Human Implements in an Abandoned River Channel in 
 Southern Oregon," "Science," vol. xxiii, p. 434. 
 
 Percy F. Kendall: "Glacial Geology of England," in "Man and the 
 Glacial Period," pp. 137-181; "Geological Observations upon some 
 Alpine Glaciers," " The Glacialists' Magazine," October, November, 
 December, 1894, January and February, 1895. 
 
 C. R. Keyes: "Eolian Origin of the Loess," "American Journal of 
 Science," 1898; "Glacial Lakes Hudson-Champlain and St. Law- 
 rence," "American Geologist," vol xxxii, pp. 223-229. 
 
 Otto Klotz: "Recession of Alaskan Glaciers," "Geographical Jour- 
 nal," October, 1907, p. 2. 
 
 F. H. Knowlton: "Notes on the Examination of a Collection of 
 Interglacial Wood from Muir Glacier, Alaska," "Journal of Geology," 
 vol. iii, pp. 527-532. 
 
 H. B. Kiimmel. "Glaciation of Pocono Knob and Mounts Ararat 
 and Sugar Loaf, Pennsylvania," "American Journal of Science," 
 February, 1896; and R. D. Salisbury: "Lake Passaic: an Extinct 
 Glacial Lake," "Journal of Geology," vol. iii, pp. 633-560. 
 
 Joseph Le Conte: "Tertiary and Post-Tertiary Changes of the 
 Atlantic and Pacific Coast, with a Note on the Mutual Relations of 
 Land-elevation and Ice-accumulation during the Quaternary Period, " 
 "Bulletin of the Geological Society of America," vol. ii, pp. 323-330; 
 
724 THE ICE AGE IN NORTH AMERICA. 
 
 "The Origin of Transverse Mountain Valleys and some Glacial 
 Phenomena in those of the Sierra Nevada," "Cal. University Chron- 
 icle," vol. xi, pp. 479-497; "The Ozarkian and its Significance in The- 
 oretical Geology," "Journal of Geology," vol, vii, pp. 525-544. 
 
 J. N. Le Conte: "Motion of Nisqually Glacier, Mt. Rainier," 
 "Sierra Club Bulletin," vol. vi, pp. 108-114. 
 
 W. T. Lee: "Note on the Glacier of Mount Lyell, California," 
 "Journal of Geology," vol. xiii, pp. 358-362; "The Glacier of Mt. 
 Arapahoe, Colorado," ibid., vol. viii, pp. 647-654. 
 
 E. D. Leffingwell: "Flaxman Island, A Glacial Remnant," "Journal 
 of Geology," vol. xvi, pp. 66-63. 
 
 Frank Leverett: "Pleistocene Fluvial Planes of Western Pennsyl- 
 vania," "American Journal of Science," September, 1891; "On the 
 Correlation of Moraines with Raised Beaches of Lake Erie," ibid., 
 April, 1892; "Further Study of the Drainage Features of the Upper 
 Ohio Basin," ibid., April, 1894; "On the Correlation of New York 
 Moraines with Raised Beaches of Lake Erie," ibid., July, 1895; "On 
 the Significance of the White Clays of the Ohio Region," "American 
 Geologist," July, 1892; "Supposed Glacial Manin Southwestern Ohio," 
 and "Relation of the Attenuated Drift Border to the Outer Moraine in 
 Ohio," ibid., March, 1893; "Relation of a Loveland, Ohio, Lnple- 
 ment-bearing Terrace to the Moraines of the Ice Sheet," " Proceedings 
 of the A.A.A.S.," vol. xl, 1891; "The Cincinnati Ice Dam," ibid.; 
 "The Glacial Succession in Ohio," "Journal of Geology," vol. i, pp. 
 129-146; "Preglacial Valleys of the "Mississippi and Tributaries," 
 ibid., vol. iii, pp. 740-763; "Changes in Drainage in Southern Ohio," 
 "Bulletin of the Scientific Laboratories of Denison Univ.," vol. ix, 
 pp. 18-21; "Correlation of Moraines with Beaches on the Border of 
 Lake Erie," "American Geologist," vol. xxi, pp 195-199; "Glacial 
 Formations and Drainage Features of the Erie and Ohio Basins," 
 "Monograph of the United States Geological Survey," xli; "Glacial 
 Geology of the Grand Rapids Area," "Michigan Geological Survey," 
 vol. ix, pp. 56-69; "The Illinois Glacial Lobe," "Monograph of the 
 United States Geological Survey," xxxviii; "Lower Rapids of the Mis- 
 sissippi River," "Journal of Geology," vol. vii, pp. 1-22; "Old 
 Channels of the Mississippi in Southeastern Iowa," "Annals of Iowa," 
 ser. 3, vol. v, pp. 38-51. "The PeorianSoil and Weather Zone (Toronto 
 Formation?)," "Journal of Geology," vol. vi, pp. 244r-249; "Pleisto- 
 cene Features and Deposits of the Chicago Area [Illinois]," "Bulletin 
 of the Chicago Academy of Science," No. ii; "Review of the Glacial 
 Geology of the Southern Peninsula of Michigan, " " Michigan Academy 
 of Science," 6th Report, pp. 100-110; "Report on the Surface Ge- 
 ology of Alcona County, Michigan," "Annual Report of the Michigan 
 Geological Survey," 1901, pp. 35-64; "Summary of the Literature 
 of North American Pleistocene Geology, 1901 and 1902," "Journal of 
 Geology," vol. xi, pp. 420-428, 498-515, 587-611; "Water Resources 
 
BIBLIOGRAPHY. 725 
 
 of Indiana and Ohio," "Eighteenth Annual Report of the United 
 States Geological Survey," pt. iv, pp. 425-559; "The Weathered Zone 
 (Sangamon) between the lowan Loess and lUinoian Till Sheet," 
 "Journal of Geology," vol. vi, pp. 171-181; "The Weathered Zone 
 (Yarmouth) between the Illinoian and Kansan Till Sheets," ibid., 
 vol. vi, p. 238-243; "Weathering and Erosion as Time Measures," 
 "American Journal of Science," May, 1909; "Wells of Northern 
 Indiana," "United States Geological Survey, Water Supply Papers," 
 No. xxix. 
 
 J. F. Lewis: "The Chicago Main Drainage Channel," "Transac- 
 tions of the American Institution of Mining Engineers," vol. xxvii, 
 pp. 288-332. 
 
 D. F. Lincoln: "Glaciation in the Finger Lake Region of New 
 York," "American Journal of Science," October, 1892; "Amount of 
 Glacial Erosion in the Finger Lake Region of New York," ibid., 
 February, 1894. 
 
 A. Lindenkohl: "Notes on the Submarine Channel of the Hudson 
 River, and Other Evidences of Post-Glacial Subsidence of the Middle 
 Atlantic Coast Region," "American Journal of Science," June, 1891. 
 
 A. P. Low: "Exploration of the South Shore of Hudson Strait," 
 "Canada Geological Survey, An. Report," vol. xi, part L, [Glacial, 
 pp. 34-47]. 
 
 B. S. Lyman: "Accounting for the Depth of the Wyoming Buried 
 Valley [Pennsylvania]," "Proceedings of Philadelphia Academy of 
 Natural Sciences," vol. liv, pp. 507-509. 
 
 W. A. McBeth: "The Development of the Wabash Drainage 
 System and the Recession of the Ice Sheet in Indiana," "Proceedings 
 of the Indiana Academy of Science," for 1900, pp. 184^192; "History 
 of the Wea Creek in Tippecanoe County," ibid., for 1901, pp. 244r-247 ; 
 "An Interesting Bowlder," ibid., for 1899, p. 162; "The Physical 
 Geography of the Region of the Great Bend of the Wabash [Indiana]," 
 ibid ., for 1899, pp. 157-161 ; " A Theory to Explain the Western Indiana 
 Bowlder Belts," ibid., for 1900, pp. 192-194; "Wabash River Terraces 
 in Tippecanoe County, Indiana," ibid., for 1901, pp. 237-243. 
 
 T. H. McBride: "A Pre-Kansan Peat Bed," "Proceedings of 
 the Iowa Academy of Science," vol. iv, pp. 63-66. 
 
 R. G. McConnell: "The Macmillan River, Yukon District," 
 "Canadian Geological Survey," Summary Report for 1902, pp. 20-36. 
 
 W J McGee: "The Pleistocene History of Northeastern Iowa," 
 "Eleventh Annual Report of the United States Geological Survey," 
 pp. 199-577. 
 
 P. C. Manning: "Glacial Potholes in Maine," "Proceedings of the 
 Portland Society of Natural History," vol. ii, pp. 185-200. 
 
 V. F. Marsiers: "Topography and Geography of Bean Blossom 
 Valley, Monroe County, Indiana," "Proceedings of the IndianaAcad- 
 emy of Science," 1901, pp. 222-237. 
 
726 THE ICE AGE IN NORTH AMERICA. 
 
 D. S. Martin: "Glacial Geology in America," "Popular Science 
 Monthly," January, 1899. 
 
 G. C. Matson: "A Contribution to the Study of the Interglacial 
 Gorge Problem," "Journal of Geology," vol. xii, pp. 133-151. 
 
 F. E. Matthes: "The Alps of Montana," "Appalachia," vol. x, 
 pp. 265-276; "Glacial Sculpture of Bighorn Mountains, Wyoming," 
 "Twenty-first Annual Report of the United States Geological Survey, ' ' 
 pt. ii, pp. 167-190; "The Lewis Range of Northern Montana and its 
 Glaciers," "Intern. Geog. Cong. 8th Report," pp. 478-479. 
 
 G. F. Matthew: "Post-Glacial Faults at St. John, New Brunswick," 
 "American Journal of Science," December, 1894. 
 
 C. J. Maury: "An Interglacial Fauna found in Cayuga Valley 
 and its Relation to the Pleistocene of Toronto, " " Journal of Geology, " 
 vol. xvi, pp. 565-567. 
 
 E. T. Mellor: "Glacial (Dwyka) Conglomerate of South Africa," 
 "American Journal of Science," August, 1905. 
 
 Frederick J. H. Merrill: "Post-Glacial History of the Hudson 
 River Valley," "American Journal of Science," June, 1891. 
 
 6. P. Merrill: Development of the Glacial Hypothesis in America," 
 "PopularScienceMonthly," April, 1906; "On the Glacial Pothole in, 
 the National Museum," "Smithsonian Miscellaneous Collections," 
 vol. xlv. pp. 100-103. 
 
 H. E. Merwin: "Some late Wisconsin and Post-Wisconsin Shore- 
 lines of North-western Vermont," "Report of the Vermont State 
 Geologist," 1907-'08, pp. 113-137. 
 
 H. R. Mill: "The Glacial Land-Forms of the Margin of the Alps," 
 "American Journal of Science," February, 1895. 
 
 A. M. Miller: "High-Level Gravel and Loam Deposits of Ken- 
 tucky Rivers," "American Geologist," November, 1895. 
 
 W. J. Miller: "Ice Movement and Erosion along the Southwestern 
 Adirondacks," "American Journal of Science," April, 1909. 
 
 H. T. Montgomery: "The Glacial Phenomena as Exhibited in North- 
 ern Indiana and Southern Michigan and the Resulting Ancient 
 Waterways, or the Early History of our Home," "Publications of 
 the Northern Indiana Historical Society," no. 2, 20 pp. 
 
 Joseph Moore: "Account of a Morainal Stone Quarry of Upper 
 Silurian Limestone near Richmond [Indiana]," "Proceedings of the 
 Indiana Academy of Science," 1896, pp. 76-76. 
 
 F. Morse: "Recession of the Glaciers of Glacier Bay, Alaska," 
 "National Geographic Magazine," January, 1908. 
 
 E.L. Moseley: " Submerged Valleys in Sandusky Bay," "National 
 Geographic Magazine," vol. xiii, pp. 398-403. 
 
 E. H. Mudge: "Central Michigan and Post-Glacial Submergence," 
 "American Journal of Science," December, 1896; "Observations 
 along the Valley of Grand River, Michigan," "American Geologist," 
 November, 1893; "Mouth of Grand River," "American Journal of 
 
BIBLIOGRAPHY. 727 
 
 Science," July, 1899; "Notes on Preglacial Drainage in Michigan," 
 ibid., August, 1900; "Some Features of Pre-GIacial Drainage in 
 Michigan," ibid., November, 1897. 
 
 John Muir: "The Pacific Coast Glaciers," "Harriman Alaska Ex- 
 pedition," vol. i, pp. 119-135. 
 
 J. N. Nevius: "History of Cayuga Lake Valley [New York]," 
 "Fifty-first Annual Report New York State Museum," vol. i, pp. 
 rl31-rl53. 
 
 Otto Nordenskjold: "Tertiary and Quartemary Deposits in the 
 Magellan Territories," "American Geologist," vol. xxi, pp. 300-309. 
 
 /. H. Ogilvie: "Effect of Superglacial Debris on the Advance and 
 Retreat of Some Canadian Glaciers," "Journal of Geology," vol. 
 xii, pp. 722-743; "Glacial Phenomena in the Adirondacks and Cham- 
 plain Valley," ibid., vol. x, pp. 379^12. 
 
 H. F. Osborn: "A Glacial Pothole in the Hudson River Shales near 
 Catskill, New York," "American Naturalist," vol. xxxiv, pp. 33-36. 
 
 Miss Luella A. Owen: "The Bluffs of the Missouri River," " Intern. 
 Geogr.-Kongr. Siebenter Verb.," pt. ii, pp. 68&-690; "Evidence on 
 the Deposition of Loess," "American Geologist," vol. xxxv, pp. 
 291-300; "The Loess at St. Joesph," ibid., vol. xxxiii, pp. 223-228; 
 "More Concerning the Lansing Skeleton," "Bibliotheca Sacra," 
 vol. Ix, pp. 572-578. 
 
 C. E. Peet: " Glacial and Post-Glacial History of the Hudson and 
 Champlain Valleys," "Journal of Geology," vol. xii, pp. 415-469, 
 617-660. 
 
 Albrecht Penck: "Climatic Features of the Pleistocene Ice Age," 
 "Geographical Journal," February, 1906; "Glacial Features in the 
 Surface of the Alps," "Journal of Geology," vol. xiii, pp. 1-19. 
 
 G. H. Perkins: "Geology of Grand Isle County [Vermont]," 
 "Vermont Geological Survey, Report of the State Geologist," iv, pp. 
 103-143. 
 
 S.J.Pierce: "Preglacial Cuyahoga Valley," "American Geologist," 
 vol. XX, pp. 176-181. 
 
 /. W. Powell: "Are there Evidences of Man in the Glacial Grav- 
 els?" "Popular Science Monthly," June, 1893. 
 
 J. A. Price and A. Shoaf: "Spy Run and Poinsett Lake Bottoms," 
 "Proceedings of the Indiana Academy of Sciences," 1900, pp. 179-181. 
 
 W. H. C. Pynchon: " Glacial Action in Connecticut, " "Connecticut 
 Magazine," vol. iv, pp. 294-303. 
 
 Charles Rabat: "Glacial Reservoirs and their Outbursts," "Geo- 
 graphical Journal," May, 1905. 
 
 T. M. Reade: "The Glacio-Marine Drift of the \Ae of Clwyd," 
 "Quarterly Journal of the Geological Society of London," vol. 53, 
 pp. 341-348. 
 
 H. S. Reed: "A Meteorological Hypothesis of the Cause of the 
 Glacial Epoch," "American Geologist," vol. xxv, pp. 109-113. 
 
728 THE ICE AGE IN NORTH AMERICA. 
 
 Harry F. Reid: "The Variations of Glaciers,'' "Journal of Geol- 
 ogy," vol. iii, pp. 278-288; "Studies of Muir Glacier, Alaska," "Na- 
 tional Geographical Magazine," vol.iv, pp. 19-84; "The Flow of Gla- 
 ciers and their Stratification," "Appalachia," vol. xi, pp. 1-6; 
 "Glaciers," "Mazama," vol. ii, pp. 119-122; "Glaciers of Mt. Hood 
 and Mount Adams, Ore.," ibid., vol. ii, pp. 195-200; "The Reservoir 
 Lagin Glacial Variations," "International Geographical Congress," 
 8th Report, pp. 487-491; "Stratification and Flow of Glaciers," 
 "Appalachia," vol, xi, pp. 1-27; "Variations of Glaciers" "Journal of 
 Geology," vol. v, pp. 378-383; vol. vi, pp. 473-476; vol. vii, pp. 217- 
 225; vol. viii, pp. 154-159; vol. ix, pp. 250-254; vol. x, pp. 313-317, 
 vol. xi, pp. 285-288; vol, xii, pp, 252-263; vol. xiii, pp. 313-318; vol. 
 xiv, pp. 402-410; vol. xvi, pp. 46-55, 664-668. 
 
 Hans Reusch: "A note on the Last Stage of the Ice Age in Central 
 Scandinavia," "Journal of Geology," vol. viii, pp. 326-332. 
 
 J. L. Rich: "Local Glaciation in the Catskill Mountains," " Journal 
 of Geology," vol. xiv, pp. 113-121; "Marginal Glacial Drainage 
 Features in the Finger Lake Region," ibid., vol. xvi, pp. 527-548. 
 
 E. P Richards: "The Gravels and Associated Deposits at New- 
 bury," "Quarterly Journal of the Geological Society of London," 
 vol. liii, pp. 420-437. 
 
 I. C. Russell: "Are there Glacial Records in the Newark System?" 
 "American Journal of Science," June, 1891; "Mt. St. Elias and its 
 Glaciers," ibid., March, 1892; " Origin of the Gravel Deposits beneath 
 Muir Glacier, Alaska, " " American Geologist, "March, 1892 ; ' ' Climatic 
 Changes indicated by the Glaciers of North America," ibid., May, 
 1892; "Notes on the Surface Geology of Alaska," "Bulletin of the 
 Geological Society of America," vol. i, pp. 99-162; "Second Expedi- 
 tion to Mount St. Elias," "Bulletin of the United States Geological 
 Survey," 1894; "Malaspina Glacier," "Journal of Geology," vol. i, 
 pp. 219-245; "The Influence of Debris on the Flow of Glaciers," ibid., 
 vol. iii, pp. 823-832; "Alaska: Its Physical Geography," "Scottish 
 Geographical Magazine," August, 1894; "Drumlin Areas in Northern 
 Michigan," "American Geologist," vol. xxxv, pp. 177-179; "Geog- 
 raphy of the Laurentian Basin," "Bulletin of the American Geo- 
 graphical Society," vol. xxx, pp. 226-254 ; "A Geological Reconnais- 
 sance along the North Shore of LakesHuronand Michigan," "Michi- 
 gan Geological Survey," Report for 1904, pp. 33-112; "Glacier 
 Cornices," "Journal of Geology," vol. xi, pp. 783-785; "Glaciers of 
 Mount Rainier," "Eighteenth Annual Report of the United States 
 GeoIogicalSurvey,"pt.ii, pp. 349-424; "Glaciers of North America," 
 "Geographical Journal," December, 1898; "Glaciers of North Amer- 
 ica; a Reading Lesson for Students of Geography and Geology," 
 (Boston, Ginn & Co., 1897); "The Great Terrace of the Columbia 
 and other Topographic Features in the Neighborhood of Lake Chelan, 
 Washington," "American Geolgist," vol. xxii, pp. 362-369; "Hanging 
 
BIBLIOGRAPHY. 729 
 
 Valleys," "Bulletin of the Geological Society of America," vol. xvi, 
 pp. 75-90; "Plasticityof Glacial Ice," "American Journal of Science," 
 April, 1897. 
 
 B. D. Salisbury: "The Drift of the North-German Lowland," 
 "American Geologist," May, 1892; "Certain Extra-Morainic Drift 
 Phenomena of New Jersey," "Bulletin of the Geological Society of 
 America," vol. iii, pp. 173-182; "Distinct Glacial Epochs and the 
 Criteria for their Recognition," "Journal of Geology," vol. i, pp. 
 61-84; "Superglacial Drift," ibid., vol. ii, pp. 613-632; "The Drift: 
 Its Characteristics and Relationships," ibid., vol. ii, pp. 708-724, 837- 
 851; "Agencies which transport Materials on the Earth's Surface," 
 ibid., vol. iii, pp. 70-97; "Preglacial Gravels on the Quartzite Range 
 near Baraboo, Wisconsin," ibid., vol. iii, pp. 655-667; "The Green- 
 land Expedition of 1895," ibid., vol. iii, pp. 875-902; papers on the 
 glacial geology of New Jersey in the State reports for 1891-1894. 
 
 R. D. Salisbury and W. W. Atwood: "Drift Phenomena in the 
 Vicinity of Devils Lake and Baraboo, Wisconsin," "Journal of Geol- 
 ogy," vol. V, pp. 131-147; "The Geography of the Region about 
 Devils Lake and the Dalles of the Wisconsin, with Some Notes on 
 its Surface Geology," "Bulletin of the Wisconsin Geological and 
 Natural History Survey," no. v, ed. ser. no. 1, pp. i-x, 1-151; and 
 others: "The Glacial Geology of New Jersey," "Final Report of 
 the New Jersey Geological Survey," vol. v; "Glacial Work in the 
 Western Mountains in 1901," "Journal of Geology," vol. ix, pp. 
 718-7,31; and E. Blackwelder; "GlaciationintheBighornMountains," 
 "Journal of Geology," vol. xi, pp. 216-223; "The Local Origin of 
 Glacial Drift," "Journal of Geology," vol. viii, pp. 426-432; "New 
 York City Folio, Pleistocene Formations," "Geological Atlas of the 
 United States," "U.S.Geol. Survey," Folio no. 83, pp. 11-17; "The 
 Surface Formations in Southern New Jersey," "Annual Report of 
 the New Jersey Geological Survey for 1900," pp. 33-40. 
 
 F. W. Sardeson; "Beginning and Recession of St. Anthony Falls," 
 "Bulletin of the Geological Society of America," vol. xix, pp. 29-52; 
 "The Folding of Subjacent Strata by Glacial Action," "Journal of 
 Geology," vol. xiv, pp 226-232; "Glacial Deposits in the Driftless 
 Area," "American Geologist," vol. xx, pp. 392-403; "A Particular 
 Case of Glacial Erosion, " ' ' Journal of Geology," vol. xiii, pp. 351-357 ; 
 "What is the Loess?" "American Journal of Science," January, 1899. 
 
 T. E. Savage; "A Buried Peat Bed in Dodge Township, Union 
 County, Iowa," "Proceedings of the Iowa Academy of Science," 
 vol. xi, pp. 103-109; "Drift Exposure in Tama County [Iowa]," 
 ibid., vol. viii, pp. 275-278; "The Toledo Lobe of lowan Drift," ibid., 
 vol. X, pp. 123-129. 
 
 H. C. Schroder and A. C.Spencer; "GeologicalandMineral Resources 
 of a Portion of the Copper River District, Alaska," U. S. 56th Cong., 
 2d Sess., House Doc. no. 546 [Glacial, pp. 58-82]. 
 
730 THE ICE AGE IN NORTH AMERICA. 
 
 E. H. L. Schwarz; "The Three Paleozoic Ages of South Africa," 
 "Journal of Geology,'' vol. xiv, pp. 683-691. 
 
 A. C. Scott: "A Brief Summary of Glacier Work," "American 
 Geologist," vol. xxx, pp. 215-261. 
 
 i\r. jS. Shaler; ' ' Tertiary and Cretaceous Deposits of Eastern Massa- 
 chusetts," "Bulletin of the Geological Society of America," vol. i, 
 pp. 443-452; "Evidences as to Changes of Sea-Level," ibid., vol. vi, 
 pp. 141-166. 
 
 W. H. Sherzer: "Glaciers of the Canadian Rockies'and Selkirks," 
 (Wash. Smithsonian Institution, 1907) ; " Ice work in Southeastern 
 Michigan," "Journal of Geology," vol. x, pp. 194-216; "Nature and 
 Activity of Canadian Glaciers," "Canadian Alpine Journal," vol. 
 i. pp. 249-263. 
 
 B. Shimek: "Additional Observations on the Surface Deposits in 
 Iowa," "Proceedings of the Iowa Academy of Science," vol. iv, pp. 
 68-72; "Is the Loess of Aqueous Origin," ibid., vol. v, pp. 32-45; 
 "The Lansing Deposit not Loess," "Bulletin of the Laboratory of 
 NaturalHistoryof Iowa State University, "vol. v, pp. 346-352; "Loess 
 and the lowan Drift," ibid., vol. v, pp. 352-368; "The Loess and 
 the Lansing Man," "American Geologist," vol. xxxii, pp. 353-369 
 "The Loess of Iowa City and Vicinity," ibid., vol. xxviii, pp. 344-358 
 "The Loess of Natchez, Mississippi," ibid., vol. xxx, pp. 279-299 
 "Nebraska Loess Man," "Bulletin of the Geological Society of 
 America," vol. xix, pp. 243-254. 
 
 C. E. Siebenthal; "Notes on Glaciation in the Sangre De Cristo 
 Range, Colorado," "Journal of Geology," vol. xv, pp. 15-22. 
 
 F. W. Simonds: "Reply to Some Statements in Professor Tarr's 
 'Lake Cayuga a Rook Basin'," "Ameiican Geologist," July, 1894. 
 
 T. B. Smyth: "The Buried Moraines of the Shunganunga [Kanas]," 
 "Transactions of the Kansas Academy of Science," vol. xv, pp. 
 95-104; "The Closing of Michigan Glacial Lakes," ibid., vol. xv, pp. 
 23-27. 
 
 J. W, Spencer: "Defoimation of the Algonquin Beach and Birth 
 of Lake Huron," "American Journal of Science," January, 1891; 
 "High-Level Shores in the Region of the Great Lakes, and their 
 Deformation," ibid., March, 1891; "Deformation of Lundy Beach and 
 Birth of Lake Erie," ibid., March, 1894: "Duration of Niagara Falls," 
 ibid., December, 1894; "The Rock Basin of Cayuga Lake, and the 
 Age of Niagara Falls," "American Geolgist," August, 1894; "Post- 
 Pleistocene Subsidence versus Glacial Dams," "Bulletin of the Geo- 
 logical Society of America," vol. ii, pp. '465-476; "A Review of the 
 History of the Great Lakes," November, 1894; " Origin of the Basins 
 of the Great Lakes of America," "Quarterly Journal of the Geological 
 Society," vol. xlvi, pp. 523-533; "Niagara as a Timepiece," "Popular 
 Science Monthly," May, 1896, pp. 1-19; "An Account of the Re- 
 searches Relating to the Great Lakes," "American Geologist," vol. 
 
BIBLIOGRAPHY. 731 
 
 xxi, pp. 110-123; "Another Episode in the History of Niagara Falls," 
 "American Journal of Science," December, 1898; "Bibliography of 
 Submarine Valleys off North America," ibid., May, 1905; "On the 
 Continental Elevation of the Glacial Epoch, ' ' ' ' British Associ ation for 
 the Advancement of Science," Report, 1897, pp. 661-662; Mr. 
 Frank Leverett's "Correlation of Moraines with Beaches on the 
 Border of Lake Erie," "American Geologist," vol. xxi, pp. 393-396; 
 "Niagara as a Timepiece," "Proceedings of the Canadian Institute, 
 New Series," vol. i, pp. 101-103; "Submarine Great Canyon of the 
 Hudson River," "American Journal of Science," January, 1905, 
 "American Geologist," vol. xxxiv, pp. 292-293; "Geographical 
 Journal," vol. xxv, pp. 180-190; " Submarine Valleys off the Amer- 
 ican Coast and in the North Atlantic," "Bulletin of the Geological 
 Society of America," vol. xiv, pp. 207-226; "The Falls of Niagara, 
 their Evolution and Varying Relations to the Great Lakes; Char- 
 acteristics of the Power and the Effects of its Diversion," "Canadian 
 Geological Survey, Department of Mines," 1907. 
 
 G. H. Squier: "Studies in the Driftless Region of Wisconsin," 
 "Journal of Geology," vol. v, pp. 825-836; vol. vi, pp. 182-192; vol. vii, 
 pp. 79-82. 
 
 C. H. Sternberg: "Experiences with Early Man in America," 
 "Transactions of the Kansas Academy of Science," vol. xviii, pp. 
 89-93. 
 
 J. J. Stevenson: "Some Notes on Southeastern Alaska and its 
 People," "Scottish Geographical Magazine," February, 1893; 
 "Recent Geology of Spitzbergen," "Journal of Geology," vol. xiii, 
 pp. 611-616. 
 
 G. H. Stone: "The Osar Gravels on the Coast of Maine," "Journal 
 of Geology," vol. i, pp. 246-254; "The Las Animan Glacier," ibid., 
 vol. i, pp. 471-474; "Was Lake Iroquois an Arm of the Sea?" 
 "Science," February 20, 1891; "Glacial Gravels of Maine and their 
 Associated Deposits," "United States Geological Survey," Mono- 
 graph xxxiv; "Glaciation of Central Idaho," "American Journal of 
 Science," January, 1900; "Gold Placers in Glaciated Regions," 
 "Mines and Minerals," vol. xx, pp. 492-404. 
 
 Avbrey Strahan: "On Glacial Phenomena of Palaeozoic Age in the 
 Varanger Fiord," "Quarterly Journal of the Geological Society of 
 London," vol. liii, pp. 137-146; "The Raised Beaches and Glacial 
 Deposits of the Varanger Fiord," ibid., vol. liii, pp. 147-156. 
 
 R. S. Tarr: "The Central Massachusetts Moraine," "American 
 Journal of Science," February, 1892; "A Hint with Respect to the 
 Origin of Terraces in Glaciated Regions," ibid., July, 1892; "The 
 Relation of the Secular Decay of Rocks to the Formation of Sedi- 
 ments," "American Geologist," July, 1892; "Glacial Erosion," 
 ibid.; September, 1893; "The Origin of Drumlins,"ibid., June, 1894; 
 "Lake Cayuga a Rock Basin," "Bulletin of the Geological Society. of 
 
732 THE ICE AGE IN NORTH AMERICA. 
 
 America," vol. v, pp. 339-356; "Arctic Sea Ice as a Geological 
 Agent," "American Journal of Science," March, 1897; "Difference 
 in the Climate of the Greenland and American Sides of Davis and 
 Baffin's Bay," ibid., March, 1897; "Drainage Features of Central New 
 York," "Bulletin of the Geol. Society of America," vol. xvi, pp. 229- 
 242; "Evidence of Glaciationin Labrador and Baffin Land," "Ameri- 
 can Geologist," vol. xix, pp. 191-197; "Former Ejrtension of Cornell 
 Glacier near the Southern End of Melville Bay," "Bulletin of the 
 Geological Society of America," vol. viii, pp. 251-268; "Glacial 
 Erosion in Alaska," Popular Science Monthly," February, 1907; 
 "Glacial Erosion in the Finger Lake Region of Central New York," 
 "Journal of Geology," vol. xiv, pp. 12-27; "Glaciation of Mount 
 Katadin, Maine," "Bulletin of the GeologicalSociety of America," 
 vol. xi, pp. 433-448; and L. Martin: "Glaciers and Glaciation of 
 Yakutat Bay, Alaska," "Bulletin of the American Geographical 
 Society," vol. xxxviii, pp. 145-167; "Gorges and Waterfalls of Cen- 
 tral New York," ibid., vol. xxxvii, pp. 193-212; "Hanging Valleys in 
 the Finger Lake Region of Central New York," "American Geolo- 
 gist," vol. xxxiii, pp. 271-290; "Margin of the Cornell Glacier," 
 vol. XX, pp. 139-156; "Moraines of the Seneca and Cayuga Lake Val- 
 leys," "Bulletin of the Geological Society of America," vol. xvi, pp. 
 215-228; "PhysicalGeography of New York State," (The Macmillan 
 Co., N. Y., 1902); "Physical Geography of New York State," pt. 8; 
 ' 'The Great Lakes and Niagara, " " Bulletin of the American Geograph- 
 ical Society," vol. xxxi, pp. 217-235, 315-343; "Position of Hubbard 
 Glacier Front in 1792 and 1794," ibid., vol. xxxix, pp. 129-136; " Post- 
 Glacial and Inter-Glacial (?) Changes of Level at Cape Ann, Massa- 
 chusetts, " " Bulletin of the Harvard College Museum of Comparative 
 Zoology," vol. 42, pp. 181-191; "Recent Advance of Glaciers in the 
 Yakutat Bay Region," "Bulletin of the Geological Society of Amer- 
 ica," vol. xviii, pp. 257-286; and L. Martin: "Recent Changes of Level 
 in Alaska," "Geographical Journal," July, 1906; "Some Instancesof 
 Moderate Glacial Erosion," "Journal of Geology," vol. riii, pp. 160- 
 173; "Valley Glaciers of the Upper Nugsuak Peninsula, Greenland," 
 "American Geologist," vol. xix, pp. 262-267; "Watkins Glen and 
 Other Gorges of the Finger Lake Region of Central New York," 
 "Popular Science Monthly," May, 1906; andB. S. Butler: "Yakutat 
 Bay Region, Alaska," "Professional Paper of the United States 
 Geological Survey," 64. 
 
 F. B. Taylor: "The Highest Old Shore Line on Mackinac Island," 
 "American Journal of Science," March, 1892; "Changes of Level in 
 the Region of the Great Lakes in Recent Geological Time," ibid., 
 January, 1895; "Niagara and the Great Lakes," ibid., April, 1895; "A 
 Reconnaissance of the Abandoned Shore Lines of Green Bay," 
 "American Geologist," May, 1894; "A Reconnaissance of the Aban- 
 dqped Shore Lines of the South Coast of Lake Superior," ibid., June, 
 
BIBLIOGRAPHY. 733 
 
 1894; "The Limit of Post-Glacial Submergence in the Highlands west 
 of Georgian Bay," ibid., November, 1894; "The Second Lalce Algon- 
 quin," ibid., February and March, 1895; "The Nipissing Beach on 
 the North Superior Shore,"ibid., May, 1895; "Preliminary Notes on 
 Studies of the Great Lakes made in 1895," ibid., April, 1896; "The 
 Ancient Strait at Nipissing," "Bulletin of the Geological Society of 
 America," vol. v, pp. 620-626; "The Champlain Submergence and 
 Uplift, and their Relation to the Great Lakes and Niagara Falls," 
 
 British Association for the Advancement of Science," Report. 1897, 
 pp. 652-653, "Correlation and Reconstruction of Recessional Ice Bor- 
 ders in Berkshire County, Massachusetts," "Journal of Geology," 
 vol. xi, pp. 323-364; "Correlation of Erie-Huron Beaches with Outlets 
 and Moraines in Southeastern Michigan," "Bulletin of the Geo- 
 logical Society of America," vol. viii, pp. 31-58; "Great Ice Dams 
 of Lakes Maumee, Whittlesey and Warren," "American Geologist," 
 vol. xxiv, pp. 6-38; "Lake Adirondack," ibid., vol. xix, pp. 392-396; 
 "Moraines of Recession and their Significance in Glacial Theory," 
 "Journal of Geology," vol. v, pp. 421-465; "Notes on the Abandoned 
 Beaches of the North Coast of Lake Superior," "American Geologist," 
 vol. XX, pp. 111-128; "Origin of the Gorge of the Whirlpool Rapids 
 at Niagara," "Bulletin of the Geological Society of America," vol. 
 ix, pp. 59-84; "Post-Glacial Changes of Attitude in the Italian and 
 Swiss Lakes," ibid., vol. xv, pp. 369-378; "Scoured Bowlders of the 
 Mattawa Valley [Ontario]," "American Journal of Science," 1897; 
 "Surface Geology of Lapeer County, Michigan; Summary Report of 
 Progress," "Annual Report of the Michigan Geological Survey," 
 for 1901, pp. 111-117. 
 
 W. G. Tight: "Contribution to the Knowledge of the Preglacial 
 Drainage of Ohio," "Bulletin of the Scientific Laboratories of Deni- 
 son University," vol. viii, pt. ii, vol. ix, pt. i; "Drainage Modifica- 
 tions in Southeastern Ohio and Adjacent Parts of West Virginia," 
 "Professional Paper of the United States Geological Survey," No. 
 13; "Drainage Modifications in Washington and Adjacent Coun- 
 ties," "Special Papers Ohio State Academy of Science," No. 3, pp. 
 11-21; "Lake Licking — a Contribution to the Buried Drainage of 
 Ohio, " ' ' Second Annual Report of the Ohio State Academy of Science, ' ' 
 pp. 17-20; " A Pre-Glacial Valley in Fairfield County [Ohio]," "Bulle- 
 tin of the Scientific Laboratory of Denison University," vol. ix, pt. 
 ii, pp. 33-37; "Some Pre-Glacial Drainage Features in Southern 
 Ohio," ibid., vol. ix, pt. ii, pp. 22-32. 
 
 J. L. Tilton: "Results of Recent Geological Work in Madison 
 County [Iowa]," "Proceedings of the Iowa Academy of Science," vol. 
 iv, pp. 47-54. 
 
 J. E. Todd: "Striation of Rocks by River Ice," "American Geolo- 
 ^st," June,. 1892; "Pleistocene Problems in Missouri" "Bulletin of 
 the Geological Society of America," vol. v, pp. 531-548; "Degreda- 
 
734 THE ICE AGE IN NORTH AMERICA. 
 
 tion of the Loess," "Proceedings of the Iowa Academy of Science," 
 vol. V, 46-51; "The Geology of Beltrami County Minnesota," "Final 
 Report of the Minnesota Geological and Natural History Survey," 
 vol. iv, pp. 131-155; "The Geology of Hubbard County and North- 
 western Portion of Cass County [Minnesota]," ibid., vol. iv, pp. 
 82-97; "The Geology of Marshall, Roseau, and Kittson Counties 
 [Minnesota]," ibid., vol. iv, pp. 117-130; "The Geology of Norman 
 and Polk Counties [IMinnesota]," ibid., vol. iv, pp. 98-116; "The Mo- 
 raines of Southeastern South Dakota and their attendant Deposits," 
 "Bulletin of the United States Geological Survey," No. 158; "New 
 Light on the Drift in South Dakota," "American Geologist," vol. 
 XXV, pp. 96-105; "New Light on the Drift in South Dakota," "Pro- 
 ceedings of the Iowa Academy of Science," vol. vi, pp. 122-130; " Re- 
 vision of the Moraines of Minnesota, " "American Journal of Science," 
 December, 1898. 
 
 /. H. Todd: "Some Observations on the Pre-Glacial Drainage ot 
 Wayne and Adjacent Counties [Ohio]," "Special Papers of the Ohio 
 Academy of Science," no. iii, pp. 47-67. 
 
 E. N. Transeau: " On the Geographic Distribution and Ecological 
 Relations of the Bog Plant Societies of Northern North America," 
 "Botanical Qazette," vol. xxxvi, pp. 401-420. 
 
 H. L. True: "The Cause of the Glacial Period" (Cincinnati, Robert 
 Clarke Co., 1902). 
 
 H. W. Turner: "Glacial Potholes in California," "American 
 Journal of Science," December, 1892. 
 
 /. B. Tyrrell: "Pleistocene of the Winnipeg Basin," "American 
 Geologist," July, 1891; "Post-Tertiary Deposits of Manitoba and the 
 Adjoining Territories of Northwestern Canada," "Bulletin of the 
 Geological Society of America," vol. i, pp. 395-410; "Notes on the 
 Pleistocene of the Northwest Territories of Canada, Northwest and 
 West of Hudson Bay," "Geological Magazine," September, 1894; 
 "Genesis of Lake Agassiz," "Journal of Geology," vol. v, pp, 78-81; 
 "Glacial Phenomena in the Canadian Yukon District," "Bulletin of 
 the Geological Society of America," vol. x, pp. 193-198; "The Glacia- 
 tion of North-Central Canada, ' ' "Report of the British Association for 
 the Advancement of Science," 1897, pp. 662-663; "Glaciation of 
 North Central Canada," "Journal of Geology," vol. vi, 147-160; "Re- 
 port on the Doobaunt, Kazan, and Ferguson Rivers and the North- 
 west Coast of Hudson Bay, and on Two Overland Routes from Hud- 
 son Bay to Lake Winnipweg," "Canada Geological Survey," n.s. voL 
 ix, Report F. 
 
 J. A. Udden: "Geology of Louisa County," "Iowa Geological 
 Survey," vol. xi, pp. 55-126; "Geology of Pottawatamie County," 
 ibid., vol. xi, pp. 199-277; "Loess as a Land Deposit," "Bulletin 
 of the Geological Society of America," vol. ix, pp. 6-9; "Loess with 
 Horizontal Shearing Planes," "Journal of Geology," vol. x, pp. 
 
BIBLIOGRAPHY. 735 
 
 245-251; "Mechanical Composition of Wind Deposits," "Augua- 
 tana Library Publications," no. 1, 69 pp.; "On the Proboscidean 
 Fossils of the Pleistocene Deposits in Illinois and Iowa," "Augus- 
 tana Library Publications," no. v, pp. 45-57. 
 
 Warren Upham: "A Review of the Quaternary Era, with Special 
 Reference to the Deposits of Flooded Rivers," "American Journal of 
 Science," January, 1891; "Recent Fossils near Boston," ibid., March, 
 1892; "Estimates of Geologic Time," ibid., March, 1893; "Epeiro- 
 genic Movements associated with Glaciation," ibid., August, 1893; 
 "Diversity of the Glacial Drift along its Boundary," ibid.. May, 1894; 
 "Late Glacial or Champlain Subsidence and Re-elevation of the St. 
 Lawrence Basin," ibid., January, 1895; "Causes and Conditions of 
 Glaciation," "American Geologist," July, 1894; "The Niagara Gorge 
 asaMeasure of the Post-Glacial Period," ibid., July, 1894; "Evidence 
 of Superglacial Eskers in Illinois and Northward," ibid., December, 
 1894; "Drumlin Accumulation," ibid., March, 1895; "Climatic Con- 
 ditions shown by North American Interglacial Deposits," ibid., 
 May, 1895; "Stagesof the Recession of the North American Ice-Sheet 
 shown by Glacial Lakes," ibid., June, 1895; "Correlations of the 
 Stages of the Ice Age in North America and Europe," ibid., August, 
 1895; "Warm Temperate Vegetation near Glaciers," ibid., November, 
 1895; "Physical Condition of the Flow of Glaciers," ibid., January, 
 1896; "The Fiords and Great Lake Basins of North America considered 
 as Evidence of Preglacial Continental Elevation and of Depression 
 during the Glacial Period," "Bulletin of the Geological Society of 
 America," vol. i, pp. 663-567; "Glacial Lakes in Canada," ibid., pp. 
 243-276; "Inequality of Distribution of the Englacial Drift," ibid., 
 vol.iii,pp. 134-148; "Relationship of the Glacial Lakes Warren, Algon- 
 qmn, Iroquois, and Hudson-Champlain," ibid., pp. ^84-487; "The 
 Champlain Submergence," ibid., pp. 508-511; "Comparison of Pleis- 
 tocene and Present Ice-Sheets," ibid., vol. iv, pp. 191-204; "Evidences 
 of the Derivation of the Karnes, Eskers and Moraines of the North 
 American Ice-Sheet chiefly from its Englacial Drift," ibid., vol. v, pp. 
 71-86; "The Succession of Pleistocene Formations in the Mississippi 
 and Nelson River Basins," ibid., pp. 87-100; "Discrimination of Gla- 
 cial Acciunulation and Invasion," ibid., vol. vi, pp. 343-352; "Drum- 
 lins and Marginal Moraines of Ice-Sheets," ibid., vol. vii, pp. 17-30; 
 "Preglacial and Post-Glacial Valleys of the Cuyahoga and Rocky 
 Rivers," ibid., pp 327-348; "Wave like Progress of an Epeirogenic Up- 
 lift," "Journal .of Geology," vol. ii, pp. 383-395; "Walden, Cochitu- 
 ate, and Other Lakes inclosed by Modified Drift," " Proceedings of 
 theBostonSocietyof Natural History," February 18, 1891; "TheOrigin 
 of Drumlins," ibid., November 16, 1892; "The Fishing Banks between 
 Cape Cod and Newfoundland," ibid., March 15, 1893; "Deflected 
 Glacial Stri»in Somerville [Mass.]," ibid., March 15, 1893; "Eskers 
 near Rochester, New York," "Proceedings of the Rochester Acad- 
 
736 THE ICE AGE IN NORTH AMERICA. 
 
 emy of Science," January 9, 1893; "Greenland Icefields and Life 
 in the North Atlantic," chapters on "The Plants of Greenland," 
 "The Animals of Greenland," "Explorations of the Inland Ice of 
 Greenland," "Comparison of Present and Pleistocene Ice-Sheets," 
 "Pleistocene Changes of Level around the Basin of the North Atlan- 
 tic," "The Causes of the Ice Age," and "Stages of the Ice Age in 
 North America and Europe," "Age of the Missouri River," "Ameri- 
 can Geologist," vol. xxxiv, pp. 80-87; "Age of the St. Croix Dalles," 
 ibid., vol. XXXV, pp. 347-355; "Antiquity of the Fossil Man of Lansing, 
 Kansas," ibid., vol. xxxii, pp. 185-187; "Antiquity of the Races of 
 Mankind," ibid., vol. xxxviii, pp. 250-254; "Ben Nevis, the Last 
 Stronghold of the British Ice-Sheet," ibid., vol. xxi, pp. 375-380; 
 "Boulders due to Rock Decay," ibid., vol. xxxiii, pp. 370-375; 
 "Causes of the Ice Age," "Journal of Transactions of the Victoria 
 Institute," vol. xxix; "Cuyahoga Pre-Glacial Gorge in Cleveland, 
 Ohio," "Bulletin of the Geological Society of America," vol. viii, 
 pp. 7-13; "The Divisions of the Ice Age," "Journal of Transactions 
 of the Victoria Institute," vol. xxxiii; "Drumlins Containing or 
 Lying on Modified Drift," "American Geologist," vol. xx, pp. 383- 
 387; "Dnmilinain Glasgow, Scotland," ibid., vol. xxi, pp. 235-243; 
 "Englacial Drift in the Mississippi Basin," ibid., vol. xxiii, pp. 369- 
 374. "Evidence of Epeirogenic Movements Causing and Terminat- 
 ing the Ice Age," "Bulletin of the Geological Society of America," 
 vol. X, pp. 5-10; "Fiords and Hanging Valleys," "American Geolo- 
 gist," vol. XXXV, pp. 312-315; "Fiords and Submerged Valleys of 
 Europe," ibid., vol. xxii, pp. 101-108; "The Fossil Man of Lansing, 
 Kansas," "Records of the Past," vol. i, pp. 272-275; "Geological 
 History of the Great Lakes and Niagara Falls," " InternationalQuar- 
 terly," vol. xi, pp. 248-265; "The Geology of Aitkin County [Minne- 
 sota]," Final Report of the Minnesota Geological and Natural History 
 Survey, vol. iv, pp. 25-54; "The Geology of Cass County and of the 
 Part of Crow Wing County Northwest of the Mississippi River [Minne- 
 sota]," ibid., vol. iv, pp. 55-81; "Geology of the Region around Red 
 Lake and Southward to Whit^Earth [Minnesota]," ibid., .vol. iv, pp. 
 155-165; "Giants' Kettles Eroded by Moulin Torrents," "Bulletin of 
 the Geological Society of America," vol. xii, pp. 25-44; "Giants' 
 Kettles near Christiania and in Lucerne," "American Geologist," 
 vol. xxii, pp. 291-299 ;" Glacial and Modified Drift in and near Seattle, 
 Tacoma, and Olympia," ibid., vol. xxxiv, pp. 203-214; "Glacial and 
 Modified Drift in Minneapolis, Minnesota," ibd., vol. xxv, pp. 273- 
 299; "Glacial History of the New England Islands, Cape Cod, and 
 Long Island," ibid., vol. xxiv, pp. 79-92; "Glacial Lake Jean Nice- 
 let," ibid., vol. xxxii, pp. 330-331; "Glacial Lake Nicolet and the 
 Portage beween the Fox and Wisconsin Rivers," ibid., vol. xxxii, 
 pp. 105-114; "Glacial Lakes and Marine Submergence in the Hudson- 
 Champlain Valley," ibid., vol. xxxvi, pp. 285-289; "Glacial Lakes 
 
BIBLIOGRAPHY. 737 
 
 Hudson-Champlain and St. Lawrence," ibid., vol. xxxii, pp. 223-230; 
 "Glacial Rivers and Lakes in Sweden," ibid., vol. xxi, pp. 230-235; 
 "How long ago was America Peopled?" ibid., vol. xxxi, pp. 312-315; 
 ' ' Man in the Ice Age at Lansing, Kansas, and Little Falls, Minnesota," 
 ibid., vol. XXX, pp. 135-150; "The Mecklenburg or Baltic Moraines," 
 ibid., vol. xxii, pp. 43-49. "Modified Drift in St. Paul, Minnesota," 
 ' ' Bulletin of the Geological Society of America, ' ' vol. viii, pp. 183-196 ; 
 "Modified Drift and the Champlain Epoch," "American Geologist," 
 vol. xxiii, pp. 319-324; "Moraines and Eskers of the Last Glaciation 
 in the White Mountains," ibid., vol. xxxiii, pp. 7-14; "New Evidence 
 of Epeirogenic Movements Causing and Ending the Ice Age," ibid., 
 vol. xxix, pp. 162-169; "Niagara Gorge and St. Davids Channel," 
 "Bulletin of the Geological Society of America," vol.ix, pp. 101-110; 
 "Outer Glacial Drift in the Dakotas, Montana, Idaho and Washing- 
 ton," "American Geologist," vol. xxxiv, pp. 151-160; "The Parallel 
 Roads of Glen Roy," ibid, vol. xxi, pp. 294-300; "Past and Future 
 of Niagara Falls," "State Reservation at Niagara, Commission," 19th 
 An. Rept., pp. 231-254; "Pleistocene Ice and River Erosion in the 
 Saint Croix Valley of Minnesota and Wisconsin," "Bulletin of the 
 GeologicalSociety of America," vol. xii, pp. 13-24: " Preglacial Ero- 
 sion in the Course of the Niagara Gorge, and its Relation to Estimates 
 of Postglacial Time," "American Geologist," vol. xxviii, pp. 235-244; 
 "Primitive Man and Stone Implements in the North American Loess," 
 "American Antiquarian," vol. xxiv, pp. 413-420; "Primitive 
 Man in the Ice Age," "Bibliotheca Sacra," vol. lix, pp. 730-743; 
 "Primitive Man in the Ice Age," "Memoirs of Explorations in the 
 Basin of the Mississippi," vol. v, Kakabikansing, pp. 116-1 19; "Primi- 
 tive Man in the Somme Valley," "American Geologist," vol. xxii, 
 pp. 350-362; "Raised Shorelines at Trondhjem [Norway]," ibid., vol. 
 xxii, pp. 149-154; "Relation of the Lafayette or Ozarkian Uplift of 
 North America to Glaciation," ibid., vol. xix, pp. 339-343; "Rhyth- 
 mic Accumulation of Moraines by Waning Ice Sheets," ibid., vol. xix, 
 pp. 411-417; " Shell-Bearing Drift of MoelTryfaen [Wales], "ibid., vol. 
 xxi, pp. 81-86; "Time Divisions of the Ice Age," "Journal of Transac- 
 tions of the Victoria Institute," vol. xxxiii, pp. 393-410; " The Toronto 
 and Scarboro Drift Series," "American Geologist," vol. xxviii, 
 pp. 306-316; "Valley Loess and the Fossil Man of Lansing, Kansas," 
 ibid., vol. xxxi, p. 25-34; "Valley Moraines and Drumlins in the 
 English Lake District," ibid., vol xxi, pp. 165-170. 
 
 F. and W. S. Vaux, Jr.: "Additional Observations on Glaciers in 
 British Columbia," "Proceedings of the Philadelphia Academy of 
 Natural Science," 1899, pp. 501-512; "The Great Glacier of the Ille- 
 cillewaet," "Appalachia," vol. ix, pp. 156-165; "Observations made 
 in 1900 on Glaciers in British Columbia," "Proceedings of Phila- 
 delphia Academy of Natural Science," 1901, pp. 213-215; "Some Ob- 
 eervations on the lUecillewaet and Asulkan Glaciers of British Colum- 
 
738 THE ICE AGE IN NORTH AMERICA. 
 
 bia," ibid., 1899, pp. 121-124; "Canadian Glaciers in Rockies and 
 SelJdrks," "Canadian Alpine Journal," vol. i, pp. 138-158. 
 
 A. C. Veatch: "Diversity of .the Glacial Period on Long Island," 
 "Journal of Geology," vol. xi, pp. 762-776. 
 
 Volk, Ernest: "The ArchEeoIogy of the Delaware Valley," "Pea- 
 body Museum Papers," vol. v. 
 
 A. R. Wallace: "The Ice Age and its Work," "Popular Science 
 Monthly," March, April, May, June, 1894. 
 
 T. L. Watson: "Some Higher Levels in the Post-Glacial Develop- 
 ment of the Finger Lakes of New York State, ' ' ' '51st. Annual Report, 
 New York State Museum," vol. i, pp. r65-rll7; "Some Notes on the 
 Lakes and Valleys of the Upper Nugsuak Peninsula, North Green- 
 land," "Journal of Geology," vol. vii, pp. 655-666. 
 
 C. L. Webster; "Preliminary Observations on Some of the Con- 
 stituent Elements of the Glacial Drift of Northern Iowa," "Iowa 
 Naturalist," vol. i, pp. 82-83. 
 
 L. G. Westgate: "Abrasion by Glaciers, Rivers, and Waves," "Jour- 
 nal of Geology," vol. xv, pp. 113-120; "The Twin Lakes Glaciated 
 Area, Colorado," "Journal of Geology," vol. xiii, pp. 285-312. 
 
 A. O. Wheeler: "Motion of Yoho Glacier," "Canadian Alpine 
 Journal," vol. i, pp. 271-375. 
 
 R. H. Whilbeck: "The Glacial Period and Modem Geography," 
 "Journal of Geography," January, 1903; "The Preglacial Course 
 of the Middle Portion of the Genessee River [New York]," "Bulle- 
 tin of the American Geographical Society," vol. xxxiv, pp. 32-44. 
 
 0. W. Willcox: "On Certain Aspects of the Loess of Southwestern 
 Iowa," "Journal of Geology," vol. xii, pp. 716-721. 
 
 E. H. Williams: "Age of the Extra-Moraine Fringe in Eastern 
 Pennsylvania," "American Journal of Science," January, 1894; 
 "Notes on Southern Ice Limit in Eastern Pennsylvania," ibid., 
 March, 1895; "Extra-Morainic Drift between the Delaware and the 
 Schuylkill," "Bulletin of the Geological Society of America," vol. 
 V, pp. 281-296; "Kansas Glaciation and its Effects on the River 
 System of Northern Pennsylvania," "Proceedings and Collections 
 of the Wyoming [Pa.] Historical and Geological Society," vol. vii, 
 pp. 21-28; "Notes on Kansan Drift in Pennsylvania," "Proceedings 
 American Philosophical Society," vol. xxxvii, pp. 84r-87. 
 
 Bailey Willis: "Ames Knob, North Haven, Maine," "Bulletin 
 of the Geological Society of America," vol. xiv, pp. 201-206; "Drift 
 Phenomena of Puget Sound," "Bulletin of the Geological Society 
 of America," vol. ix, pp. 111-162. 
 
 5. W. Williston: "The Fossil Man of Lansing Kansa.s," "Popular 
 Science Monthly," vol. Ixii, pp. 463^73; "On the Lansing Man," 
 "American Geologist," vol. xxxv, pp. 342-346; "The Pleistocene of 
 Kansas," "Kansas University Geological Survey," vol. ii, pp. 299-308; 
 "Transactions of the Kansas Academy of Science," vol. xv, pp. 90-94. 
 
BIBLIOGRAPHY. 739 
 
 A. W. G. Wilson: "Glaciation of Orford and Sutton Mountains, 
 Quebec," "American Journal of Science," March, 1906; "Physical 
 Geology of Central Ontario," Can. Inst., Trans., vol. vii, pp. 139-186. 
 
 A. N. Winchell: "Age of the Great Lakes of North America: A 
 Partial Bibliography, with Notes," "American Geologist," vol. 
 xix, pp. 336-339. 
 
 N. H. Winchell: "The Geology of Lake County [Minnesota]," 
 "Final Report of the Minnesota Geological and Natural History 
 Survey," vol. iv, pp. 266-312; "The Geology of the Northern Portion 
 of St. Louis County [Minnesota]," ibid., vol. iv, pp. 222-265; "Geology 
 of the Southern Portion of St. Louis County [Minnesota]," ibid., vol. 
 iv, pp. 212-221; "Glacial Lakes of Minnesota," "Bulletin of Geolog- 
 ical Society of America," vol. xii, pp. 109-128; "The Lansing [Kan- 
 sas] Skeleton," "American Geologist," vol. xxx, pp. 189-194; "The 
 Pleistocene Geology of the Concannon Farm, near Lansing, Kansas," 
 ibid., vol. xxxi, pp. 263-308; "Was Man in America in the Glacial 
 Period?" "Bulletin of the Geological Society of America, vol. xiv, 
 pp. 133-152. 
 
 J. B. Woodworth: "Post-Glacial Eolian Action in Southern New 
 England," "American Journal of Science," January, 1894; "Some 
 Typical Eskers of Southern New England," "Proceedings of the Bos- 
 ton Society of Natural History," February 7, 1894; "Ancient Water 
 Levels of the Champlain and Hudson Valleys," "Bulletin of theNew 
 YorkState Museum," No. 84, pp. 265; "Glacial Origin of Older Pleis- 
 tocene in Gay Head Cliffs, with Note on Fossil Horse of that Sec- 
 tion," "Bulletin of the Geological Society of America," vol. xi, 
 pp. 455-460; "Ice-Contact in the Classification of Glacial Deposits," 
 "American Geologist," vol. xxiii, pp. 80-86; "Pleistocene Geology 
 of Mooers Quadrangle, being a Portion of Clinton County, includ- 
 ing Parts of the Towns of Mooers, Champlain, Altona, Chazy, Dan- 
 nemora, and Beekmantown, New York," "Bulletin of the New York 
 State Museum," No. 83, pp. 3-60; "Pleistocene Geology of Portions 
 of Nassau County and Borough of Queens [New York]," ibid., 
 no. 48, pp. 618-670; "Some Glacial Wash-Plains of Southern New 
 England," "Bulletin of the Essex Institute," vol. xxix, pp. 71-119. 
 
 Mrs. F.B. Workman: " Ascent of the Great ChogoLoongma Glacier, 
 and other Climbs in the Himalayas," " Appalachia," vol. x, pp. 241- 
 255; "Further Exploration in the Hunza-Nagar and the Hispar 
 Glacier," "Geographical Journal," November, 1908. 
 
 W. H. Workman: "Exploration of the Nun Kun Mountain Group 
 and its Glaciers," "Geographical Journal," January, 1908. 
 
 A. A. Wright: "Nikitin on Quaternary Deposits of Russia, and 
 their Relations to Prehistoric Man," "American Journal of Science," 
 June, 1893; "Extra-Morainic Drift in New Jersey," "American Geol- 
 ogist," October, 1892; "LimitsoftheGlaciatedAreainNew Jersey," 
 "Bulletin of the Geological Society of America," vol. x, pp. 7-13. 
 
740 THE ICE AGE IN NORTH AMERICA. 
 
 G. F. Wright: "Theory of an Interglacial Submergence in Eng- 
 land," "American Journal of Science," January, 18^; "Unity of the 
 Glacial Epoch," ibid., November, 1892; "Continuity of the Glacial 
 Period," ibid., March, 1894; "Observations on the Glacial Phe- 
 nomena of Newfoundland, Labrador, and Southern -Greenland," 
 ibid., February, 1895; "Dr. Hoist on the Continuity of the Glacial 
 Period," "American Geologist," December, 1895; "The Supposed 
 Post-Glacial Outlet of the Great Lakes through Lake Nipissing and 
 the Mattawa River," "Bulletin of the Geological Society of America," 
 vol. iv, pp. 423-427; "Age of Second Terrace on the Ohio at Brilliant, 
 near Steuben ville," "Journal of Geology," vol. iv, pp. 218, 219; "Man 
 and the Glacial Period," "Popular Science Monthly," July, 1891; 
 "Evidencesof GlacialMan in Ohio," ibid.. May, 1893; "The Cincin- 
 nati Ice Dam," ibid., June, 1894; "New Evidence of Glacial Man in 
 Ohio," ibid., December, 1895; "Extra-Morainic Drift in the Susque- 
 hanna, Lehigh, and Delaware Valleys," "Proceedings of the Phila- 
 delphia Academy of Natural Science," December 27, 1892; "Man and 
 the Glacial Period," "Science," November 11, 1892; "Some Detailed 
 Evidence of an Ice Age in Eastern America," ibid., February 3, 1893; 
 "Mr. Holmes's Criticism upon the Evidence of Glacial Man," ibid., 
 May 19, 1893; "Glacial Phenomena between Lake Champlain, Lake 
 George, and the Hudson River," ibid., November 22, 1895; "Age of 
 the Philadelphia Brick Clay," ibid., February 14, 1896; "Man and 
 the Glacial Period" ("International Scientific Series," D. Appleton 
 & Co., 1892; second edition, 1894); "Greenland Icefields, and Life 
 in the North Atlantic, with a New Discussion of the Causes of the 
 Ice Age" (D. Appleton & Co., 1896) ; "Age of the Lansing Skeleton," 
 "Records.of the Past," vol. ii, pp. 119-124; "The Ancient Gorge of 
 Hudson River," ibid., vol. iv, pp. 167-171. "Another Glacial Won- 
 der," "The Nation," vol. 77, pp. 462^63; " Chronology of the Glacial 
 Epoch in North America," (Abstract) "Quarterly Journal of the 
 Geological Society of London," vol. Ixiv, pp. 149-151; "Evidence of 
 the Agency of Water in the Distribution of Loess in the Missouri 
 Valley," "American Geologist," vol. xxxiii, pp. 205-222; "Glacial 
 Man," "Records of the Past," vol. ii, pp. 259-271; "Glacial Move- 
 ments in Southern Sweden," "American Geologist,'' vol. xxxvi, pp. 
 269-271; "The Influence of the Glacial Epoch upon the Early His- 
 tory of Mankind," "Journal of Transactions of the Victoria Insti- 
 tute," vol. xl; "The Lansing Skull and the Early History of Man- 
 kind," "Bibliotheca Sacra," vol 'x, pp. 28-32; "New Method of 
 Estimating the Age of Niagara Falls," "Popular Science Monthly," 
 June, 1899; "Origin and Distribution of the Loess in Northern China 
 and Central Asia," "Bulletin of the Geological Society of America," 
 vol. xiii, pp. 127-138; "The Physical Conditions in North America 
 during Man's Early Occupancy," "Records of the Past," vol. iv, 
 pp. 15-26; "Prof. Shimek's Criticism of the Aqueous Origin of Loess," 
 
BIBLIOGRAPHY. 741 
 
 "American Geologist," vol. xxxv, pp. 236-240; "Rate of Lateral 
 Erosion at Niagara," ibid, vol. xxix, pp. 140-143; "Report of the 
 Boulder Committee of the Ohio State Academy of Sciences," "Ohio 
 State Academy of Sciences," 2d An. Report, pp. 5-10; 3d An. Report, 
 pp. 6-7; "The Revision of Geological Time," "Bibliotheoa Sacra," 
 vol. Ix, pp. 578-582. 
 
INDEX. 
 
 Aar Glacier, 196, 256, 256. 
 
 Abbeville, Prance, 623, 624. 
 
 Abbott, Dr. C. C, finds palseoUthlc Imple- 
 ments at Trenton, N. J., 541, 619, 621, 
 625 et aeq., 642, 646, 674; on early man In 
 Ohio, 641. 
 
 Abbott, Richard, 628. 
 
 Ackley, Pa., 149, 160, 327. 
 
 Adams, Mr. Charles Francis, 701. 
 
 Adams county, Ohio, 170. 
 
 Adams Glacier, 72. 
 
 AdelphI, Ohio, 169, 242. 
 
 Adljondacks, 241, 357, 358, 487; terraces 
 on, 30. 
 
 Africa, glaclatlon In South, 485. 
 
 Aftonlan episode, 224. 
 
 Agasslz, A., on recent elevation of Peru, 
 507. 
 
 Agasslz, Louis, discovers glacial motion, 
 2; on depth of glaciers, 195; on termi- 
 nal moraines in Ammonoosuc Valley, 
 N. H., 221; on parallel roads of Glen 
 Roy, 364. 
 
 Agassiz Glacier, 30. 
 
 Aire Glacier, 449-461. 
 
 Atry, Sir George B., 498. 
 
 Akron, Ohio, 353. 
 
 Alaska, islands ot, 16, 23, 43, 55, 189; glac- 
 iers of, 25 et seq., 40 et seq., 188, 462, 488, 
 490; condition of northern, 37; burled 
 forests of, 62; rainfall of, 68, 190. 
 
 Alaskan Peninsula, glaciers on, 36. 
 
 Albany, N. Y., 329. 
 
 Aletsch Glacier, 104, 231, 364. 
 
 Alexander Archipelago, 188, 192. 
 
 Alleghany Mountains, 133, 242, 299, 362, 
 371, 526. 
 
 Alleghany River, 370,604; valley of ercslon, 
 228, 300; preglacial drainage of, 307, 308; 
 glacial drainage of, 314, 376; terraces on, 
 328. 
 
 Alleghany Valley, 161. 
 
 Alpine glaciers, terminal moraines of, 16; 
 19; velocity of, 80; size of, 81, 84; depth of, 
 104, 195, 201, 448; recession and a'dvance 
 of, 105, 496, 600; subglaclal streams of, 
 264, 255; former estenslon of, 512. 
 
 Alps, bowlders of, 236, 237, 249; lakes in, 
 364, 365; erosion of, 231, 254, 255, 278; 
 plants on, 429, 436; insects of, 438. 
 
 Amerallk Fiord, 99. 
 
 Amherst, Ohio, 124. 
 
 Andes, existing glaciers In, 108; Quater- 
 nary uplifts of, 607, 511, 512; ancient 
 glaciers In, 6;12. 
 
 Andover, Mass., kames in, 339; kettle- 
 boles in, 572. 
 
 Andover, Me., 349. 
 
 Andrews,Dr. E., ondateof glacial period, 
 508,517,671,665. 
 
 Androscoggin River, 221, 342, 349. 
 
 Animal remains In glacial deposits, near 
 Morgantown, W. Va., 378; In valley of 
 the Somme, 624; at Trenton, N. J., 639; 
 In California, 690. 
 
 Animals, extinction of, during the Glacial 
 period, 436, 706. 
 
 Antarctic Continent, glaciers of, 104, 112; 
 Icebergs of , 112 et seq. ; depth of Ice In, 201 . 
 
 Antarctic exploration, 120, 121. 
 
 Apennines, 429. 
 
 Appalachian Mountains, 229, 269, 299, 362, 
 487; correlated with Carboniferous or 
 Permian glaclatlon, 48i , 516. 
 
 Archibald, Pa., 331. 
 
 Arkansas River, 173, 22i . 
 
 Armstrong, Dr. A., on transported bowl- 
 ders in the Hudson Bay region, 245. 
 
 Aroostook River, 343. 
 
 Asbury, Pa., 148. 
 
 Asia, 490; glaciers of, 104, 107, 108; loess In, 
 i07 eiseq.; existing plants of northeastern, 
 422, 426; temperature of northern, 478;' 
 glaclatlon of, 484,486; absence of general 
 glaclatlon In, 513. 
 
 743 
 
744 
 
 INDEX. 
 
 Asslnibom River, 333, 335, 545. 
 
 Atrevlda Glacier, 32, 606. 
 
 Attenuated border, 174, 581, 582; chapter 
 on, 151-166; in Pennsylvania, 153; age of, 
 how determined, 155; formed by glacial 
 streams, 156; Chamberlln on, 174. 
 
 Auk Glacier, 27. 
 
 Avalanche Lake, 13. 
 
 Aunt Ann's Run, Ohio, 600. 
 
 Australia, Carboniferous or Permian glac- 
 ial deposits in, 516. 
 
 Babbitt, Miss Franc, palseollthlc discover- 
 ies of, 619, 621, 654, 655 et seq. 
 
 Baffin Bay, 92, 527. 
 
 Bainbridge, Ohio, 242, 326, 372, 561. 
 
 Bakersfield, Vt., 347. 
 
 Bakewell, Mr., on rate of recession of Ni- 
 agara Falls, 539. 
 
 Baldwin, Mr. Prentiss, 40. 
 
 Baltimore and Ohio Railroad cut, 669. 
 
 Bancroft on the antiquity of man, 699. 
 
 Barbour, Mr. E. H., 683, 685. 
 
 Barnstable county, Mass., 137. 
 
 Bassett's Creek, 553, 554. 
 
 Bauerman, H., 505. 
 
 Beaches raised, 401, 404, 405, 500, 504, 505, 
 655, 664. 
 
 Beach Haven, Pa., 133, 148, 326. 
 
 Beardslee, Commander, 43. 
 
 Beardslee Islands, 43. 
 
 Bears, 436. 
 
 Beaver county. Pa., 242. 
 
 Beaver Creek, 308, 309. 
 
 Becker, G- F., on glaclatlonand erosion of 
 the Sierra, 568, 569; on snow fall in, 570. 
 
 Beech City, Ohio, 326. 
 
 Beech Flats, Ohio, 373, 374, 384. 
 
 Belcher, Sir Edward, visits Kotzebue 
 Sound, 37. 
 
 Bell, Dr. R . , 505, 670; on transported bowl- 
 ders in the Hudson Bay region, 246; on 
 Portland promontory, 569. 
 
 Bellevue, Pa., 375, 376, 384. 
 
 Belvidere, N. J., 142, 326, 637. 
 
 Benton, Mr. E. R., on the Richmond train 
 of bowlders, 239, 240. 
 
 Benton, Pa., 148. 
 
 Berg Lake, 'i2. 
 
 Bessels, Dr., on transported bowlders in 
 the Hudson Bay region, 245. 
 
 Bethlehem, Pa., 637. 
 
 Big Beaver River, 300, 314, 326-328. 
 
 Bigger township, Ind., 601. 
 
 Big Sandy River, 300, 382, 384. 
 
 Big Stone Lake, 316, 354. 
 
 Blrtle, Manitoba, .335. 
 
 Bismarck, Dakota, 174, 244, 526. 
 
 Blsoi, 37, 436, 675, 690. 
 
 Black River, Ohio, recession of falls of, 560. 
 
 Blake, Mr. William P., on Glaciers of the 
 Stiokeen River, 25, 27. 
 
 Blandford, W. T., 510. 
 
 Blennerhassett Island, 327. 
 
 Block Island, 137. 
 
 Blue Mountains, N. J., 133, 144. 
 
 Blue Ridge. See Kittatlimy Mountain/ 
 
 Bolivar, Ohio, 326. 
 
 Bonney, T. G., on cirques, 274. 
 
 Boone county, Ky., terminal moraine In, 
 170; bowlders m, 243, 367, 368, 385, 386. 
 
 Borden, Professor, reports vegetal deposits, 
 602. 
 
 Boston, Mass., and vicinity, 123, 137, 281 
 et seq., 453, 488, 504. 
 
 Bottomley, Mr., experiment by, 5. 
 
 Bousslagault, M., experiment by, 4. 
 
 Bowlder-clay. See Till. 
 
 Bowlders, 132, 133; size of, 174, 180, 185, 236 
 et seq., 484, 485; elevation of, in ice, 197, 
 246 etseq.; transportation, 2dQetseq., 238, 
 484. 
 
 Bownocker, Professor, on Kanawha drain- 
 age, 309; on Middle Ohio drainage, 309. 
 
 Bradford, Mass., 237. 
 
 Brady Glacier, 74. 
 
 Brainerd, Minn., 660, 661. 
 
 Branner, Professor J. C, on depth of ice 
 In Pennsylvania, 197. 
 
 British America, 463; terminal moraine in, 
 133; Missouri coteau in, 133, 176, 215 et 
 seq., 244; depth of ice in, 199-201; trans- 
 portation of bowlders In, 176, 202, 244 et 
 seq.; erosion in, 259; glacial drainage In, 
 333 et seq.; preglacial plants of, 425. 
 
 British Columbia, 176, 278; glaciers of, 15, 
 139, 179, 191; Islands of, 23; rivers of, 25; 
 wells In, 185; oscillations of, 505. 
 
 British Isles, maximum post-glacial up- 
 lift, 191, 506. 
 
 Brooklyn, N. Y., 140, 360. 
 
 Brown county, Ind., 170, 243, 601. 
 
 Brown county, Ohio, glacial boundary In, 
 170, 526; bowlders in, 242. 
 
 Brown, Robert, on Vancouver Island, 185, 
 186, 188; on Greenland, 602. 
 
 Brown's Valley, 316. 
 
 Brunswick, Me., 343. 
 
 Brush Creek, 372 et seq., 384. 
 
 Buffalo, N. Y., 396, 398, 540. 
 
 Burbank, Mr. L. S., on preglacial erosion, 
 261. 
 
 Burchill, Mr., reports wood in a well, 
 601. 
 
INDEX. 
 
 745 
 
 Burled channels, In trough of the Ohio, 300, 
 301, 309, 644; in Knox county, Ohio, 301; 
 connecting Beaver Creek with Grand 
 Elver, 303; In Clark county, Ohio, 302; 
 connecting Lake Ontario with the Hud- 
 son, 303; In Cuyahoga county, Ohio, 304; 
 between Lakes Huron and Ontario, 305; 
 in Michigan and Illinois, 306; In Penn- 
 sylvania, 307, 311, 333; In New York, 305, 
 308; In Canada, 313; relation of, to min- 
 ing Interests, 332; from Whirlpool to St. 
 Davids, 537; In Minnesota, 553 et seq. 
 
 Burled forests at Mulr Glacier, 62 et seq., 
 233, 234, 592; theory of, 576, 579; In Ohio. 
 692, 593; in Alaska, 606. 
 
 Bute Inlet, 186. 
 
 Butler county, Ohio, striae In, 591 ; organic 
 remains In glacial deposits in, 592, 598 et 
 
 . seq., 601, 603. 
 
 Butterflies, Alpine species of, upon the 
 White Mountains, 438. 
 
 Cairo, 111., 228. 
 
 Calaveras skull, 693 et seq., 697 et seq., 700. 
 
 California, 409; existing glaciers in, 13 et seq. ; 
 ancient glaciers in, 176, 177, 179, 180; ter- 
 minal moraines In, 222; prehistoric man 
 m, 417, 688; flora of, 426; river beds of, 
 688 et seq. 
 
 Camel, 436, 690. 
 
 Campbell county, Ky., 170, 367. 
 
 Canada, 341, 313, 325; depth of ice In, 301; 
 of till in, 258; biu-ied channels in, 304, 312; 
 lake ridges of, 398; salt deposits of, 464. 
 
 Canadian Pacific Hallway, 13, 25. 
 
 Canadian Rockies, glaciers in, 13. 
 
 Canton, Ohio, 168, 336. 
 
 Cape Agassiz, 97. 
 
 Cape Breton Island, absence of Quaternary 
 marine beds on, 504. 
 
 Cape Cod, 137, 130, 140, 207, 237, 238, 343. 
 
 Cape Dudley Digges, glacier near, 86. 
 
 Cape Forbes, 97. 
 
 Cape St. Roque, 473. 
 
 Carboniferous glacial epochs, 487, 609, 515, 
 518. 
 
 Caribou, 675. 
 
 Carl, Mr., on preglaclal drainage, 302, 307, 
 308. 
 
 Carmlchaels, Pa., 603. 
 
 Carr, Mr. Lucien, finds palaeoliths, 637. 
 
 Carroll county, N. H., 351. 
 
 Carroll Glacier, 73. 
 
 Carrollton, N. Y., 308. 
 
 Carver visits Falls of St. Anthony, 657. 
 
 Cascade range, 15, 19, 23, 135, 177, 178, 191, 
 193^ 417. 
 
 Cat, 436. 
 
 Catskill Mountains, 147, 195, 198. 
 
 Cattaraugus county, N. Y., 149, 308, 398. 
 
 Caucasus Mountains, 107, 429. 
 
 Cause of the Glacial period, chapter on, 
 461-531 ; not strictly a geological question, 
 461, 529; cold not a sufficient, 461; theo- 
 ries of the, enumerated, 463 ; not a shifting 
 of the poles, 463; not solely excessive 
 moisture, 464; not the depletion of car- 
 bon dioxide in the atmosphere, 464, 465; 
 changes In the distribution of land and 
 water, a possible, 495 et seq. ; continental 
 elevations a probable, 496 et seq.; varia- 
 tions In the temperature of space, and the 
 heat of the sun, £i possible, 466; CroU's 
 theory of, 466 et seq., 629; precession of 
 the equinoxes, a, 466 et seq.; changes In 
 eccentricity of the earth's orbit, a, 468; 
 changes In the Gulf Stream, 469 et seq.; 
 relation of trade-winds to, 470; of Cape 
 St. Roque to, 472 et seq,; relativecoolness 
 of the southern hemisphere, a, 474, 475; 
 Woeikoft''s explanation, 475, 476; Ignor- 
 ance of the laws governing the distribu- 
 tion of the heat upon the earth, 477, 530; 
 inequality of this distribution, 478, 629; 
 diathermancy of the atmosphere, 479, 
 630; defective evidence of former glacial 
 periods, 481 et seq., 530; local centers of 
 dispersion, 525 et seq., 531; indirect Influ- 
 ence of Greenland lee, 527; present Ignor- 
 ance of, 528, 531. 
 
 Cedar wood in glacial deposits, 692, 598-600, 
 603. 
 
 Centers of radiation, 179, 307 et seq.; 527. 
 
 Central Pacific Railroad, 608. 
 
 Chaleurs, Bay of, marine beds overlying 
 glacial drift In, 504. 
 
 Chalmers, Robert, 504. 
 
 Chamberlin, Pres. T. C, 391, 600, 662, 563; 
 on the Greenland glaciers, 103; on the 
 position of bowlders In clay, 130; on rock- 
 scoring, 133; discovers terminal moraine, 
 134; on loess, 172.412, 413; attenuated bor- 
 der, 174; on glacial boundary in Dakota, 
 176; west of Dakota, 176; on moraine of 
 central New York, 306; on moraine west 
 of the Aileghanles, 207; on tne Kettle 
 Range, 311, 212, 221, 528; on depth of till, 
 258; on drumllns, 286, 292; on CroU's 
 theory of successive glacial epochs, 489, 
 675; on post-glacial denudation in Wis- 
 consin, 568; on two glacial epochs, 575, 
 578. 
 
 Champaign county, Ohio, 257, 258. 302. 
 
 Chaney Glacier, 13. 
 
746 
 
 INDEX. 
 
 Chappaqulddlck Island, 137. 
 
 Charpentler Glacier, 74. 
 
 Charleston, W. Va., 379. 604. 
 
 Chatham Strait, 42, 59. 
 
 Chazy, N. Y., 320, 347. 
 
 CherryBeld, Me., 348. 
 
 Cherry Valley, Pa., 195 et seq., 247. 
 
 Chesapeake and Ohio Railroad cut, 379. 
 
 Chewtown. Pa., 326. 
 
 Cheyenne Elver, 174, 175, 244, 336, 545. 
 
 Chicago, 111., 547. 
 
 Chill, glaciers In, 104, 108, 109. 
 
 Chllkat, Alaska, 27, 29. 
 
 Chllllcothe, Ohio, 242, 326, 561, 602. 
 
 China, loess In, 407 et seq.; flora of, 426, 
 
 427. 
 Chippewa Creek, 542. 
 Chrlstlanshaab Glacier, 99. 
 Chugatch Alps, Alaska, glaciers on, 36. 
 Cincinnati, Ohio, 170, 301, 302, 327, 367, 592, 
 
 643, 644; glacial dam at, 366 et seq., 394, 
 
 603. 
 Cirques, description of. 272; formation of, 
 
 274 et seq., 355; prevalence of, 277. 
 Clark county, Ohio, 302. 
 Clarksburg, W. Va., 378. 
 Claymont, Del., palseollthic Implement 
 
 discovered at, 669 et seq. 
 Claypole, Professor B. W., 498; on depthof 
 
 drift, 257; on Cincinnati Ice-dam,385-387 
 
 et seq.; on the Deluge, 438. 
 Cleaverlng, explorations by, 98. 
 Clermont county, Ohio, glacial boundary 
 
 In, 170; bowlders In, 242; vegetable de- 
 posits In, 602. 
 Cleveland, Ohio, 304, 367. 
 Climate, preglaclal about the north pole, 
 
 424, 430, 437. 
 Close, Mr. M. H., on drumllns, 290, 291. 
 Coast Range, 15, 23, 186, 193, 429. 
 Colchagua, 109. 
 Cole's Spring, N. Y., 308. 
 Coleman, Professor A. P., 584, 685, 587. 
 CoUett, Professor, reports vegetable depos- 
 its In Indiana, 603. 
 Collomb, M. E., on subglaclal streams in 
 
 the Alps, 255. 
 Colorado, 222, 274, 441; former glaciers In, 
 
 176, 177. 
 Colorado River, 228. 
 Cols, 156, 158, 159, 160, 163, 164, 309, 310, 317, 
 
 319, 336, 393, 394, 642, 663, 587. 
 Columbia deposits, 633 et seq., 671. 
 Columbia River, 228. 
 Columbiana county, Ohio, fringe in, 167; 
 
 terminal moraine in, 168; bowlders In, 
 
 242, 326. 
 
 Columbus, Mount Vernon, and Akron 
 Railroad cut, 169. 
 
 Concord, N. H., 330. 
 
 Conewango Creek, 149-150, 162, 307,308, 326. 
 
 Connecticut, depth of Ice In, 195, 199; 
 transported bowlders In, 238; depth of 
 till in, uncertain, 259; drumllns In, 285. 
 
 Connecticut River, 283, 342, 343, 345 et aeq., 
 660; glacial drainage of, 330, 331, 486, 635. 
 
 Connell, Mr. J. M., reports wood in a well, 
 602. 
 
 Contocook River, 330. 
 
 Contractions of the earth, probably causing 
 glaciation, 497, 499, 509, 514. 
 
 Cook, Captain, 35; on Icebergs of the South- 
 ern Ocean, 116, 116. 
 
 Cook, F. A., 99, 100. 
 
 Cook, Professor George H., 639, 675; dis- 
 covers terminal moraine, 134, 221; mo- 
 raines of retrocession, 207; on trans- 
 ported bowlders, 241. 
 
 Coral islands indicating subsidence, 508. 
 
 Cornish, N. H., 361. 
 
 Coteau des Prah-Ies, 212, 214, 362, 416, 662. 
 
 Coulee, 219, 331. 
 
 Cowlitz River, 21. 
 
 Crenate character of the glacial margin, 
 132, 133, 442 et seq. 
 
 Cresson, Mr. H. T., palseolithic discover- 
 ies of, 619, 622; at Medora, Ind., 649-663; 
 at Claymont, Del., 669, 671 et seq., 675. 
 
 Crevasses. See Fissures. 
 
 CroU, Mr. J., 497, 509, 512, 516-518; theory 
 of glacial motion, 6; on Icebergs In South- 
 ern Ocean, 117 et seq.; on depth of ice in 
 the Antarctic Continent, 201; theory of 
 the Cause of the Glacial period, 466 et 
 seq.. 532, 634, 562; on date of Glacial 
 period, 574, 604; on post-glacial erosion 
 In Scotland, 568; on succession of glacial 
 periods, 481 et seq. ,575; on rate of denu- 
 dation, 614. 
 
 Crosby, Professor W. 0., 238, 507, 509. 
 
 Cross Sound, 29, 42, 43, 59-61, 189. 
 
 Crust, relation of the earth's, and Interior, 
 498, 502, 694. 
 
 Cuba, post-glacial elevation of, 507. 
 
 Gumming, Mr. G. M., 702. 
 
 Cuyahoga River, 303. 
 
 Cypress Hills, 199, 200. 
 
 Dakota, glacial boundary in, 133, 172 et 
 seq., 441, 442; marginal drainage In, 174, 
 176, 332 ; fringe In, 174; Coteau des Prairies 
 In, 212, 214, 362, 415; Missouri coteau In, 
 215, 217, 332; bowlders In, 243, 244; lakes 
 In, 362; loess In, 243, 416. 
 
INDEX. 
 
 747 
 
 Dall, W. H., explorations of, In Alaska, 29j 
 In Kotzebue Sound, 37; In northern 
 Alaska, 38. 
 
 Dana, Professor J. D., 327, 497, 498, 609, 
 514, 619, 628; on depth of loe, 199, 201; on 
 kames In the Connecticut Valley, 346; 
 on the floods of the Connecticut Valley, 
 346, 635. 
 
 Dauvflle, Ohio, 169. 
 
 Darrtown, Ohio, 698. 
 
 Darwin, Charles, 614, 706; on glaciers o 
 South America, 109 et seg.; on dust- 
 storms, 409; on earthworms, 418. 
 
 Darwin, Professor G. H., 497. 
 
 Date of the Glacial period, 376, 641, 666, 
 508, 517; chapter on, 532-615; astronomi- 
 cal evidence Insufficient, 532; calcula- 
 tions of afifected by unlformltarlanism, 
 533; tendency to make more recent, 533; 
 question of, geological, not astronomical, 
 534; calculated from the erosion below 
 Niagara Falls, 536 et scg.; below the 
 Falls of St. Anthony, 662 et aeq.; from 
 falls In northern Ohio, 560; from Paint 
 Creek cut-off, 561; from erosion of Rac- 
 coon Creek, 564; of Plum Creek, 565- 
 567; from the shores of Lake Michigan, 
 571; from deposition In kettle-hole, 
 Andover, Mass., 572; bearing of theory 
 of successive Glacial periods upon the 
 subject of, 575; freshness of vegetable 
 deposits Indicates a recent, 592 et seq.; 
 burled peat-beds no bar to theory of 
 a recent, 694 e( seg. ; evidence from Lakes 
 Lahontan and Bonneville concerning, 
 607 et seq.\ Prestwichon, 613. 
 
 Davidson Glacier, 27. 
 
 Davis, Professor William M., on drumllns, 
 284, 285 et seg., 290 etseq.; on glacial lakes, 
 364, 366. 
 
 Davis Strait, 85, 449. 
 
 Dawkins, Professor Boyd, on the origin 
 of bowlderwjlays of Britain, 448, 449; 
 visits Trenton.N. J., 619, 628, 629. 
 
 Dawson, G. M., 179, 505, 506; discovers 
 terminal moraine, 134; on Missouri co- 
 teau, 176,217e«acg.;on glacial phenom- 
 ena of Bute Inlet, 186 et seq, ; expedition 
 to the Yukon, 190; on depth of ice, 199; 
 on transportation of bowlders, 199, 202, 
 244, 245; on the glacial theory, 200; on 
 j unction of two Ice-streams of the North- 
 west, 213; on cirques, 278; on glacial 
 drainage, 333. 
 
 Dawson, Sir William, 601, 504; on prehto- 
 toric man In California, 698. 
 
 Dead Sea, Palestine, gravel deposits about 
 the, records of the Glacial period, 612. 
 
 Deblols, Me., 348. 
 
 Delaware, paleeolithic discoveries in, 669 
 et seq. 
 
 Delaware River, 133, 136, 141, 144, 145, 228, 
 326, 326, 358, 634, 633, 634, 635, 636, 639, 
 640, 669, 671, 675. 
 
 Delaware Water-Gap, 146, 196, 197, 228, 247 
 et seg., 260, 352, 633, 637. 
 
 Delta terraces, 326 et seq.; in New Hamp- 
 shire, 330; in Minnesota, 334; In Maine, 
 348, 349; on Cape Cod and Long Island, 
 349; in Wisconsin, 360. 
 
 Deluge, the, perhaps connected with the 
 Glacial period, 438. 
 
 Depth of ice duringthe Glacial period, 413, 
 603, 504, 519; in Yellowstone Park, 177 
 in California, 180; In Maine, 194, 196; In 
 New Hampshire, 194; in Vermont, 194 
 in Massachusetts, 195; in Connecticut, 
 195, 199; in New York, 195, 261; in Penn- 
 sylvania, 196, 197, 198; In New Jersey, 
 198, 634; in British America, 199, 200; 
 over the region of the Great Lakes, 200, 
 201; In Greenland, 201, 202; in the Alps, 
 201,448; in the Antarctic Continent, 201 
 in Labrador, 202 ; in Norway, 447 ; on the 
 Harz Mountains, 417; in Scotland, 448 
 In England, 450; effect on snow-fall, 628. 
 
 Desor, on depth of glaciers, 195; on erosion 
 In the Alps, 256 ; on rate of recession of 
 Niagara Falls, 639. 
 
 DevU's Lake, 211. 
 
 Diamond Peak, 19. 
 
 Diller, Mr., on glaciers of the Cascade 
 Range, 19. 
 
 Dirt Glacier, 72. 
 
 Disco Bay, 76. 
 
 Disenchantment Bay, 31, 32. 
 
 District of Columbia, 671. 
 
 Dixon's Entrance, 30. 
 
 Dog, 436. 
 
 Dolager's nunataks, 81. 
 
 Dolfus, on erosion in the Alps, 254. 
 
 Dolphins, 436. 
 
 Don River, Can., 584, 585. 
 
 Driftless area of WlscoiLSIn, 134, 413, 523. 
 
 Drumllns, chapter on, 281-297; locality of, 
 281, 284 et seg.; description of, 22, 282 et 
 seq.; Upham on, 282, 289, 292; direction 
 of the axesof , 283, 284, 287, 289, 292 ; Davis 
 on, 284 et seq., 290 et seq. ; in northeastern 
 Massachusetts, 284; Percival on, 286; 
 Johnson on, 286, 291; Chamberlin on, 
 286, 292; theory of, 287 et seg.; absence of 
 kettle-holes in, 288; earlier than kames. 
 
748 
 
 INDEX. 
 
 288; Shaler on, 288; King on, 288; Hitch- 
 cock on, 290, 292; Close on, 290; Gelkle 
 on, 291. 
 
 D'Urville, Explorations of, in the Antarc- 
 tic Continent, 114. 
 
 Dust-fo?s, 409, 410. 
 
 Button, Captain C. E., 498. 
 
 Dying Glacier, 73. 
 
 Eagle, Wis., 211, 350. 
 
 Earthworms and loess, 418. 
 
 Easton, Pa.,142,634. 
 
 Eccentricity of the earth's orbit, varia- 
 tions of, 468, 518 ; not coincident with the 
 latest epoch of glaclation, 509, 517; prob- 
 ably not influential in causing glacl- 
 ation, 518. 
 
 Elephants, 436, 437, 634. 
 
 Elevation of bowlders in ice, in Pennsyl- 
 vania,197, 241 , 247 etseq. ; InBrltish Amer- 
 ica, 200, 244; in Massachusetts, 237, 239, 
 240; in New Hampshire, 246, 247; in Ver- 
 mont, 247; in Maine, 247; explanation of, 
 250e(seg. 
 
 Elevation probably causing glaclation, 
 497, 508 et seq. ; due to removal of the Ice- 
 sheet, 499, 500, 506. 
 
 Elizabeth Islands, 137, 140, 203, 360. 
 
 Elliott, H. W., on Alaskan glaciers, 30. 
 
 Ells, Mr. R. W., on buried channels in 
 Canada, 312. 
 
 Ellsmere Land, glaciers in, 102. 
 
 Elyria, Ohio, 560. 
 
 Emerson, Professor, on marginal lakes of 
 the Connecticut Valley, 347. 
 
 Emmons, Mr. S. F., ascent of Mount Ta- 
 coma by, 22. 
 
 England, 229, 534; glaciers in, 446, 448 et 
 seq.; changes of level In, 453; palseollths 
 in, 616, 624; preglaclal man in, 534, 676. 
 
 Bquador, 108. 
 
 Erichsen, M., 99. 
 
 Erosion by water, 226 et seq., 279, 298 et 
 seq., 372, 488, 536 et seq.; compared with 
 that of Ice, 227, 355; chemical, 229, 568; 
 glacial, 230 et seg.; preglacial, 226 et seq.; 
 261 , 298 e( seq. ; post-glacial ,298, 536et seq . 
 
 Eschscholtz Bay, 36, 37. 
 
 Eskers. See Karnes. 
 
 Eskimos, 245, 440, 623, 641 ; lineal descend- 
 ants of preglacial man, 438, 706, 707. 
 
 Essex County, Mass., 285, 289. 
 
 Europe, existing glaciers of, 104 et seq., 110, 
 glacial erosion in, 231, 232, 264,255, 260, 
 278, 294 et seq.; transported bowlders in, 
 236, 237 ; drumlins in, 290, 291 ; kames In, 
 339, 340; glacial lakes in, 364, 365 ; loess In, 
 
 410 ; preglacial plants of, 428 ; e£ seq. ; dur- 
 ing the Glacial period, chapter on, 445- 
 459; successive Glacial periods In, 483- 
 486; Interglaclal man in, 623-625; Qua- 
 ternary oscillations in, 506. 
 
 Evans, Mr., 624. 
 
 Swing, Professor A. L., on chemical eros- 
 ion in the Nittany Valley, 229, 230. 
 
 Fairfield county, Ohio, glacial boundary 
 in, 169; bowlders In, U2. 
 
 Falconer, Dr., 624. 
 
 Falls of Minnehaha, post-glacial, 303. 
 
 Falls of Niagara, 575; post-glacial,- 303; 
 formation of, 536; rate of recession of, 
 536e(se5.,665, 706. 
 
 Falls of St. Anthony, 311, 575, 655; post- 
 glacial, 303, 552 et seq. ; rate of recession 
 of, 557eJse(7.; 665. 
 
 Falmouth, Mass., 204 et seq. 
 
 Fargo, Minn., 334. 
 
 Faroe Islands, 506. 
 
 Favorite Glacier, 74. 
 
 Finger Lakes, New York, 206, 352, 353, 
 358, 363. 
 
 Fiords, 501, 502, 506. 
 
 Fisher, Rev. O., 498. 
 
 Fisher's Island, 140. 
 
 Fishing Creek, 148. 
 
 Fissures in glacial ice, 8, 19, 50, 93, 95, 96. 
 
 Flathead River, 13. 
 
 Floodsat the close of the Glacial period, 
 314 et seq., 346 et seq., 387 et seq., 558, 634- 
 638. 
 
 Floras of Faroe Islands and Iceland, 506. 
 
 Florence, Ky., 367. 
 
 Fondalen Glacier, 106, 233. 
 
 Foote, Professor H. C, onsedimentof sub- 
 glacial streams, 68. 
 
 Forbes, Professor J. D., discovers glacial 
 motion, 2, 88, 94; on transported bowl- 
 ders in the Alps, 237. 
 
 Forel, M., on recession and advance of 
 Alpine glaciers, 105. , 
 
 Fort SnelUng, 315, 665; contrast between 
 bluffs above and those below, 553, 554. 
 
 Fort Wrangel, 27, 39, 136, 188. 
 
 Foshay, Mr. P. Max, on buried channels, 
 302. 
 
 Fosslliferous marine beds overlying glacial 
 drift, 504, 505. 
 
 Fossils at Glens Ferry, 704 et seq. 
 
 Posters Flats, 550. 
 
 Four-mile Creek, Ohio, 598, 600. 
 
 France, 487; dust-shower in, 410; palaeo- 
 lithsin, 616, 623, 624; Interglaclal man In, - 
 676. 
 
INDEX. 
 
 749 
 
 Frankfort, Ohio, 602. 
 
 Franklin, Pa., 326, 328. 
 
 Franz-Joseph Land, 107. 
 
 Fraser River, 25, 228. 
 
 Frederlckshaab Glacier, 100, 101, 366; 
 
 sloijeof, 201. 
 Freehold, Pa., 508. 
 French Creek, Pa., 308, 326, 328. 
 Frere, Mr. John, 624. 
 Fringe, the, of the glaciated area, 167, 174, 
 
 234,244. 
 
 Gabb, Mr. William M., 507. 
 
 Gastaldl, B., on cirques, 274; on glacial 
 deposits In Italy, 486. 
 
 Gelkle, Professor A ., 498, 510, 512; on the 
 extent of glaclatlon In Europe, 447, 448; 
 In Scotland, 483. 
 
 Gelkle, Professor James, 497, 506, 609, 512, 
 517 ; on drumllns, 291 ; on glacial erosion, 
 294 et seq.; on composition of kames, 
 339, 340; on Glacial period in Great 
 Britain, 445, 449; theory of cause of Gla- 
 cial period, 466 et seq,; on glaclatlon In 
 Scotland, 484. 
 
 Gelkle Glacier, 74. 
 
 Genesee River, 303. 
 
 Germantown, Ohio, 592, 593, 597, 598. 600. 
 
 Gibraltar Island, Ohio, 266. 
 
 Gibraltar, Strait of, migrations across, 507. 
 
 Gletroz Glacier, 365. 
 
 Gilbert, Mr. G. K., 498, 508, 517, 542, 612; 
 on the moraine of Maumee Valley, 207 
 e2 8e9.,266;onlake ridges, 395; on CroU's 
 theory of successive glacial epochs, 489, 
 575; on recession of Niagara Falls, 540; 
 on Lake Bonneville, 611 ; on date of Gla- 
 cial period, 665. 
 
 Gilder, Mr. Robert F., 683. 
 
 Girdled Glacier, 72. 
 
 Glacial boundary in North America, ser- 
 rate character of, 132; crenate character 
 of, 132, 133; chapters on, 134-167; dis- 
 coverers of, 134; not always a terminal 
 moraine, 135; south of New England, 
 137 et seq.; across New Jersey, 140, 141; 
 across Pennsylvania, 145 et seq.; limits 
 of error respecting, 148 et seq.; in New 
 York, 149 et seq.; in Ohio, 167 et seq.; in 
 Kentucky, 170; in Indiana, 170; in Illi- 
 nois, 170, 315; beyond the Mlsslsssippl, 
 172 ; beyond the Missouri, 174 ; in British 
 America, 176; beyond the Rooky Moun- 
 tains, 176 et seq.; in California, 179; in 
 Washington State, 182; in British Co- 
 lumbia, 183; in Alaska, 189; cause of Ir- 
 regularity, 441 ; notes, 604. 
 
 Glacial dams, 355, 535, 665; in the Cone- 
 wango, 150; at the mouth of the Lehigh, 
 153; across Kansas and Platte Rivers, 
 172, 414; In headwaters of Arkansas and 
 Platte Rivers, 177; In Leevining River, 
 222; in New Hampshire, 363; in New 
 York, 363; in New Jersey, 363; in the 
 Alps,364; in Scotland, 364; in Greenland, 
 366; In the Ohio at Cincinnati, 366 et seq., 
 603; in England, 451. 
 Glacial deposits contrasted with aqueous, 
 129 etseq.; factors determining extent of, 
 135, 203; cause of stratification in, 142. 
 Glacial drainage, terraces produced by, 
 150, 319, 323 et sea.; chapter on, 313-336; 
 floods of , 313 et seq. ; from the Red River 
 basin, 313, 315, 316; in the valleys of thf 
 Mohawk and Hudson, 329 ; from the Con- 
 tooook Valley, N. H., 330; in Grafton 
 county, N. H., 331; in eastern Penn- 
 sylvania, 332; in Dakota, 175, 332, 336; 
 from the valley of the Saskatchewan. 
 333; in southwestern Manitoba, 334; in 
 southern Minnesota, 336; marked by 
 kames, 341, 348; in the Talley of the Con- 
 necticut, 346 et seq., 635; In the Little 
 Miami, 644. 
 Glacial erosion, In the State of Washing- 
 ton, 22; manner of, 230 et seq. ; variation 
 of, 232 ; small near the margin, 233 et seq. ; 
 In Greenland, 253, 256; in the Alps, 254, 
 278 ; in British America, 257, 278 ; In Penn- 
 sylvania, 196, 260; In Scandinavia, 260; 
 as effected by secular disintegration, 261 
 et seg.; at the west end of Lake Erie, 262 
 et seq. ; of rock basins in the high Sierra, 
 267; in the Yosemite Valley, 270, 271; of 
 cirques, 271 et seq.; Russell on, 272; Lo- 
 range on, 276; of fiords, 278; of lake- 
 basins in Europe, 278; summary con- 
 cerning, 279 etseq.; J. Gelkle on Inequal- 
 ities of, 294 et seq. 
 Glacial lakes, 356 et seq., 415, 416, 665; on 
 Pocono Mountain, 148; in Kansas and 
 Platte Rivers, 172, 414; in the Platte and 
 Arkansas, 177; in Leevining River, 222; 
 In the Sierra, 269; in Contocook Valley, 
 N. H., 330; kinds of, 359 ; occupying kei- 
 tle-holes, 359 et seq. ; caused by dams of 
 glacial dibris, 362 et seq.; Lake Wlnne- 
 pesaukee, 363; In New York and New 
 Jersey, 363; caused by dams of Ice, 364 
 et sea.; In the Alps, 364; In Scotland, 364; 
 in Greenland, 366; in the Ohio, 370, 386; 
 in England, 451. 
 Glacial periods, supposed succession of, 
 468, 481 et seq., 488, 533; lack of evidence 
 
750 
 
 INDEX. 
 
 GoncerDing, explained, 481 ; In Great 
 Britain, 483, 484; in South Africa and 
 India, 484, 485; in Switzerland and Italy, 
 486 ; in North America, 486 et seq. 
 Glacial striae. See Rock Scoring. 
 Glacial theory, confirmations of, 130, 132, 
 133, 143, 183, 240, 323, 326 et seq., objec- 
 tions to, by Canadian geologists, 200. 
 Glaciatlon, probable causes, 497-519. 
 Glaclatton, signs of former, chapter on, 
 108-133; scratches on the rocks, 123 et 
 seq.; unstratlfied deposits, 129 et seq.; 
 distribution of bowlders, 132, 133. 
 Glacier Bay, Alaska, 27, 39, 43, 44, 55, 61, 
 
 72, 74, 136, 188, 592. 
 Glaciers, ancient, in the Rocky Mountains , 
 176; in the Sierra Nevada, 177 et seq.; in 
 the British Isles, 445, 446, 448 et seq., 483; 
 In' Scandinavia, 447; in Germany, 456; 
 in India, 484, 485; in South Africa, 485; 
 in the Andes, 512. 
 
 Glaciers,- existing, in the Rocky Moun- 
 tains, 13 ; In the Sierra Nevada, 13 et seq. ; 
 In southern California, 13; on Mount 
 Shasta, 15; on Mount Hood, 19; on 
 Mount Tacoma, 21 ; on Fraser River, 25 ; 
 on Stickeen River, 25; in Taku Inlet, 
 27; of Lynn Canal, 27; of Mount St. 
 Ellas, 30, 600; of Yakutat Bay, 30; of 
 Chugatch .Alps, 36; of the Alaskan Pe- 
 ninsula, 36; in Glacier Bay, iOet seq.; In 
 Greenland, chapter on, 75-102; in Ells- 
 mere Land,102;lnGrinnell Land,102;in 
 the Alps, 104, 105; In Scandinavia, 104, 
 105;in Spitzbergen, Nova Zembla, and 
 Franz-Josef Land, 107; in Iceland, 107; 
 in Asia, 108; In South America, 108 ef 
 seq.; In New Zealand, 112; in the Ant- 
 arctic Continent, 112 et seq.; in Green- 
 land, 602. 
 
 Glaciers, movements oi, 2, 80, 296; seml- 
 fiuidlty of, 3, 4, 81; structure of, 7; slope 
 of, 18, 47, 77, 78, 85, 88, 95, 108, 198, 201, 
 202, 392; velocity of, 3, 54, 78, 80, 82, 105, 
 202; thickness of, 19, 22, 47, 77,79,81,85, 
 91, 93, 104, 113, 114, 118, 119, 201, 202, 
 
 Glen Roy, parallel roads of, 364. 
 
 Godfrey's Ridge, Pa., 197, 247. 
 
 Gould, Dr. D. T., on burled channels In 
 Ohio, 304. 
 
 Grafton county, N. H., 330, 331. 
 
 Grafton, W. Va., 370. 
 
 Grand Pacific Glacier, 73, 
 
 Grand Tower, 111., 171. 315. 
 
 Granville, Ohio, 564, 603. 
 
 Gravitation of the ocean toward the Ice- 
 sheet, 503. 
 
 Gray, Professor Asa, 513; list of Alaskan 
 plants identified by, 69; on distribution 
 of plants in the northern hemisphere, 
 422 et seq. 
 Great Lakes o' North America, 436; depth 
 o ' Ice over, 200, 201 ; erosion In beds of, 260 
 etseq.; formation of, 262, 356 et seq., 500, 
 501; Newberry on, 262, 356 et seq; pre- 
 glacial outlets of, 304 et acq.; glacial 
 drainage of, 313, 314, 317, 319; depths of, 
 356; influence of ice-barriers on, 390 et 
 seq. 
 Great Miami River, 170, 300, 301, 323. 326, 
 
 327, 644. 
 Great Salt Lake, 396, 607, 609. 
 Greeley, A. W., on the Greenland glaciers, 
 
 102. 
 Green Bay, Wis., 211, ^12, 528. 
 Green Mountains, 194; terraces on, 30. 
 Greenland, the glaciers of,' chapter on, 
 75-102; area of, 75, 93; interior condi- 
 tion of, 75, 84, 447; Nordeoakioldon, 77; 
 Rink on, 77 et seq.; thickness of ice In, 
 77, 79, 82, 85, 201, 202, 503; rate of motion 
 of. 78, 80, 82 ; explorers of 80, Helland on, 
 80; subglacial streams of, 82, 255; Icebergs 
 from, 82, 85, 95, 235; Whymper on, 83 et 
 seq.; Kane on, 86 et seq., 93 et seq., 235; 
 Hayes on, 89 et seq.; north of 79°, 92; on 
 the eastern coast, 97; Nansen on, 98; 
 Eriohsfin on, 99; erosion in, 253, 255, 256; 
 Marr on, 366; Preglacial plants of, 424, 
 425, 430, 462; Preglacial climate of, 380. 
 463; Insects of, 439; cause of glaciers tn, 
 463 ; during the Glacial period, 527; post- 
 glacial elevation of, 507. 
 Grlnnell Expedition, 86. 
 Grinnell Land, glaciers in, 102; post-glac- 
 ial elevation of, 583. 
 Grooves. See Rock Scoring. 
 Grote, Mr. A. R., on the White Mountain 
 
 butterfly, 439 et seq. 
 Ground moraine. See Till. 
 Gulf of Mexico, 416, 472. 
 Gulf Stream, possible changes in, 495, 508, 
 effeet o., on the Atlantic, 469; cause of, 
 470 et seq. 
 Guyandotte River, 379, 381, 38'', 604. 
 
 Haenke Glacier, 32. 
 
 Haenke Island, 31. 
 
 Hal!, Professor James, 500; on elevation 
 of bowlders, 24S; on drift hills of New 
 York, 286; on rate of recession of Niag- 
 ara Falls, 539. 
 
 Hamilton county, Ohio, 242, 602. 
 
 Hamilton, Ohio, 128, 131, 600,614. 
 
INDEX. 
 
 751 
 
 Hanover, N. H., 345. 
 
 Hartwlg, G.,on glaciers of Magdalena Bay, 
 107. 
 
 Haughton, Professor S., on transported 
 bowlders in the Hudson Bay region, 245. 
 
 Haverhill Mass., 338. 
 
 Hayes, I., explorations of, in the Saint 
 Ellas range, 30; in Greenland, 8G, 89 et 
 seq. 
 
 Haynes, Professor H. W., on palseoliths, 
 619 et seq., discovers palseoliths, 628, 629. 
 
 Helland, Mr. A., 445; on rate of movement 
 of Greenland glaciers, 80, 82, 302; on 
 slope of Jakobshavn glacier, 201; on ero- 
 sion in Greenland, 255; In Scandinavia, 
 260; on depth of drift In Germany and 
 Russia, 260, on formation of cirques, 
 274. 
 
 Hennepin discovers Falls of St. Anthony, 
 557. 
 
 Herschel, Sir John, 500. 
 
 Hice,Mr.,309. 
 
 Hicks, Professor, on Raccoon Creek, 564, 
 565. 
 
 Hlgglnsport, Ohio, 170. 
 
 Highland county, Ohio, 170, 591, 602. 
 
 Hilgard, Professor E. W., 513; on loess, 
 410, 411, 415; on depression in Mississippi 
 Valley, 410, 411. 
 
 Hillsborough county, N. H., 330. 
 
 Himalayan Mountains, 108, 365, 427; Qua- 
 ternary uplift of, 510, 513. 
 
 Hind, Professor, on glacial drainage, 335. 
 
 Hlnde, Dr. G. J., 584. 
 
 Hippopotamus, 690. 
 
 Hitchcock, President E., on size of bowl- 
 ders, 236 et aeq. ; on the Richmond train 
 of bowlders, 239; on kames in Andover, 
 Mass., 339. 
 
 Hitchcock, Professor Charles, 504; on ele- 
 vation of bowlders, 194, 246, 247; on 
 depth of Ice, 202 ; on lenticular hills, 281, 
 283, 290, 292; on buried kame In Hano- 
 ver, N. H., 345; on CroU's theory, 574. 
 
 Hocking River, 300, 323, 326. 
 
 Holkham Bay, 27. 
 
 Holmes county, Ohio, terminal moraine 
 In, 169; bowlders In, 242; glacial terraces 
 in, 326. 
 
 Hoist, N. 0., 239, 586; on the Greenland 
 glaciers, 100, 101. 
 
 Hopkins, Professor W., 497. 
 
 Horse, 436, 438, 690. 
 
 Horseshoe Fall, Niagara, recession of, 540. 
 
 Hudson Bay,199, 246, 3S4, 356, 607. 
 
 Hudson Bay and Strait, raised beaches of, 
 504. 
 
 Hudson River, 136, 228, 305, 329, 352, 357, 
 368; submarine fiord of, 305, 306, 502, 
 503. 
 
 Hugh Miller Glacier, 73. 
 
 Humboldt Glacier, 91 et seq. 
 
 Humboldt Range, 177. 
 
 Hunt, Professor Sterry, on preglacial ero- 
 sion, 261. 
 
 Hunter, Captain.on depth of Muir Glacier, 
 45. 
 
 Huntingdon Mountain, 148. 
 
 Hurricane Creek, W. Va., 381, 382. 
 
 Hutton, Captain, 510. 
 
 Icebergs, on coast of Alaska, 35; from Muir 
 Glacier, 40, 50, 51, 67; from Greenland, 
 85, 96; In Straits of Magellan, HI; of the 
 Antarctic Continent, 112, 114 e^ seq. ; for- 
 mation of, 235. 
 
 Iceberg theory, 126, 133, 143, 183, 200 et seq., 
 240. 
 
 Ice, characteristics. of, 1 et seq., 232; is but 
 compressed snow, 6. 
 
 Iceland, 107, 430, 441, 582. 
 
 Ice-plUars, 10, 49, 70. 
 
 Ice-sheet, advance of, 313; retreat of, 139, 
 150, 221, 314, 315, 316, 343, 349, 352, 387 et 
 seq., 398, 558, 623, 654, 661; causing de- 
 pression of the earth's crust, 416, 417, 
 497, 500, 510; probably due to elevation, 
 497,509,511. 
 
 Icy Bay, 30. 
 
 nieclllewaet Glacier, 13, 14. 
 
 Illinois, drlftless area of, 134; depth of ice 
 in, 201 ; glacial boundary In, 170-172, 525, 
 526, 528; bowlders in, 243; depth of drift 
 in, 257; loess In, 415, 587; striae In, 591; 
 buried wood In glacial deposits in, 601. 
 
 Illinois River, 314, 354. 
 
 Illlnoisan deposits, 223, 590. 
 
 Implement-bearing gravels in Europe, 
 616, 624, et aeq.; at Trenton, N. J., 630 
 et seq., 669, 706; at MadlsonviUe and 
 Loveland, Ohio, 644 et seq., 669, 706; at 
 Medora, Ind., 649 et seq., 669, 706; at 
 Little Falls, Minn., 656 et seq., 669, 706; 
 at Claymont, Del., 669 et seq. 
 
 India, 487, 510, 613, 516; glaciers of, 108, 365; 
 Permian glacial deposits in, 485, 516. 
 
 Indian Ridge in Andover, Mass., 339. 
 
 Indiana, glacial boundary In, 170, 207, 525, 
 526, 528; bowlders in, 243, 652; depth of 
 drift in, 257, 601, 602; wells in, 300, 601, 
 
 . 602; loess in, 415, 587; striae In, 591 ; vege- 
 table deposits in, 601, 602, 603; palaeo- 
 lithic implements in, 649 et seq. 
 
 Indianapolis, Ind., 170. 
 
752 
 
 INDEX. 
 
 Insects, migrations of, during the Glacial 
 period, 438 ei seq. ; Alpine species of but- 
 terflies upon the White Mountains, 438. 
 
 Interglacial deposits, how preserved, 295 
 et seq.; theory of, 576; in Ohio, 592, 598; 
 in Minnesota, 605, 607. See Vegetable 
 Remains in Glacial Deposits. 
 
 Interglacial epoch, evidence favoring, 575 
 el seq., 607 el seq.; duration of, 512, 562, 
 563; probable causes of, 497, 512. 
 
 Interglacial man, in France, 616, 623; In 
 England, 616, 624; at Trenton, N . J., 625 
 et seq.; at Madiaonville and Loveland, 
 Ohio, 643 et seq.; at Medora, Ind., 619 et 
 seq.; at Little Falls, Minn., 653 et seq.; at 
 Claymont, Del., QGQetseq.; in Nebraska, 
 675; in Tuolumne county, Cal., 689 et 
 seq.; Le Conte on, 688 et seq., 699; Daw- 
 kins on, 699. 
 
 Interglacial migrations from Africa to 
 Europe, 507. 
 
 Interior moraines, 140, 204, 207 et seq. 
 
 Interior, probable condition of the earth's 
 498, 502, 618. 
 
 Iowa, 362, 525, 628, 661; drlftless area of, 
 134, 414; depth of ice In, '!01; bowlders in, 
 243; lakes in, 361; loess in, 113-416; veg- 
 etable deposits in, 605. 
 
 lowan deposits, 223. 
 
 Ireland, 11, 339, 360, 361, 445, 446, 448. 
 
 Irish Sea Glacier, 446, 449-451. 
 
 Isblink, 79. 
 
 Italy, 'lactation in, 486, 
 
 Jackson county, 111., 171, 172, 243. 
 
 Jackson county, Ind., 170, 601, 649. 
 
 Jackson. Dr. Sheldon, on depth of Muir 
 Glacier, 45. 
 
 Jackson, Mr. C. T., cited, 331. 
 
 Jacobus Creek, 352. 
 
 Jakobahavn Glacier, 78, 80; rate of dis- 
 charge, 82, 85; slope of, 201,202;subgla- 
 clal streams of, 255; glacial damsof, 366. 
 
 Jamaica, post-glacial elevation of, 507. 
 
 James, Professor Joseph F., on burled 
 channels in the Ohio, 301. 
 
 James River, Dakota, 211, 215, 336. 
 
 Jamieson, T. F.. 498, 500, 501. 
 
 Japan, flora of, 423, 426, 431, 432, 434; dust- 
 fog in, 409. 
 
 Jefferson county. Ind., 602. 
 
 Jennings county. Ind.. 601. 
 
 Jensen. A.D., 80. 81, 201. 
 
 Johns Hopkins Glacier, 73. 
 
 Johnson, Dr.L.,ondruinllnsinNewYork, 
 286,291. 
 
 JohnsonviUe, Pa., 352. 
 
 Jones, Dr., 701. 
 Jtlvdliarsuk Glacier. 79. 
 Juneau, Alaska, 27, 59. 
 
 Kamchatka, 430, 441. 
 
 Kames In Rindge, N. H., 330; In Wlnchen- 
 don. Mass.. 330; chapter on. 339-354;Ed- 
 ward Hitchcock's description of , 339; J. 
 Geikie's description of, 339; structure of, 
 340; compared with terminal moraines, 
 340; theory of. 11, 16, 66. 341; forming 
 at the Muir Glacier. Alaska, 66, 342; sys- 
 tem of,ln NewEngland, 342; burled, 345; 
 in the Connecticut Valley, 345; Dana on, 
 346, 347; at Stroudsburg, Pa.. 348, 352; 
 deltas of, 348, 352; m Rangely Lakes, 
 349; location of, prognosticated, 349, 350; 
 of backward drainage. 350 et seq.; in 
 Schoodlc Lake. 350; near Osslpee Lake, 
 351; near Portland, Pa., 352; near the 
 Finger Lakes, N. Y., 352; in Ohio, 353; 
 absence of, in the Northwest. 353; com- 
 pared to a skeleton. 354. 
 
 Kanawha River, 300, 309, 379, 381, 383, 604. 
 
 Kane, Dr., explorations of in Greenland, 
 86, 87, 92 et seq. ; on formation of Icebergs, 
 235. 
 
 Kansan drift, 153, 154, 158, 224. 585, 588. 
 
 Kansas, glacial boundary in. 172; loess in, 
 414, 415. 
 
 Kansas City, Mo., 172, 412. 
 
 Kansas River, 172. 114. 
 
 Karajak Glacier. 78. 
 
 Keewatin ice center. 685, 586. 
 
 Kelley's Island, 262. 
 
 KenaiPeninsula, glaciers on, 36. 
 
 Kennebec River, 221, 342. 
 
 Kenton county, Ky., 367. 
 
 Kentucky, 170. 201, 243, 367. 368. 375. 385. 
 386. 487. 
 
 Kettle-holes, defined, 11; formation of, in 
 front of Muir Glacier. 57. 66; in Ply- 
 mouth county. Mass., 139, 360; explan- 
 ation of, 143; resemble sink-holes. 143; 
 formation of. 144. 204. 369. 360, 572; 
 on Pooono Mountain, 148; near Ack- 
 ley, Pa.. 150; in Ohio. 168. 169, 597; abun- 
 dance of. In terminal moraine, 204,360, 
 361 ; Professor Koons on , 204 e( se^. ; direc- 
 tion of longer axis or. 201. 205; in New 
 England. 360, 361 ; age of. estimated, 572 
 et seq. ; near Freehold, Pa., 698. 
 
 Kettle Range, Wis., 134, 144, 207,211, 212, 
 221,361,415.527. 
 
 King. Mr. Clarence, 198; on glaciers of 
 Mount Shasta, 15 et seq. ; discovers ter- 
 minal moraine, 131, 221; report on fortl- 
 
INDEX. 
 
 753 
 
 eth parallel, 177 et seq.; on Yosemlte 
 Valley, 271; on drumllns, 288; on dust- 
 fogs, 409. 
 
 Klnnahan on drumllns, 290. 
 
 Kittatlnny Slountaln, 133, 146, 228; eleva- 
 tion of bowlders ou, 196, 247 et seq.; ero- 
 sion on, 260. 
 
 Knox county, Ohio, glacial boundary In, 
 169; burled channel In, 301; terraces In, 
 326. 
 
 Koldewey, Captain, on east coastof Green- 
 land, 98. 
 
 Koons, Professor B. F., on kettle-boles, 
 20ietaeq. 
 
 Kryokonlte defined, 9. 
 
 Kuro-Slwa, 495. 
 
 Kurtz, Mr. M. A., 701. 
 
 Kuskovlm River, 36. 
 
 Labrador, depth of Ice In, 202 ; Insects in, 
 439-441 ; aoenterof show-fall,527,585,586. 
 
 Lake Agassiz, 401 et seq., 559, 654, 655 ; delta 
 terrace In, 334 ; beaches of , 401 , 404 et seq., 
 500, 543, 545, 655, 664; vegetable deposits 
 In bed of, 603, 607; Upham on, 401 et seq., 
 543 et seq. 
 
 Lake Allegheny, 158-160. 
 
 Lake Arlkaree, 336. 
 
 Lake Bonneville, 336, 609, 611, 612, 704. 
 
 Lake Calhoun, 555. 
 
 Lake Champlaln, 358, 363. 
 
 Lake Chautauqua, 308, 363. 
 
 Lake Erie, 201, 354, 395, 542; Islands of, 262 
 etseq. ; preglaclaloutletof , 303 etaeg., 536; 
 glacial drainage of, 314, 317 ;forniationof, 
 356 et sea., 363; beaches of, 545. 
 
 Lake Harriet, 555. 
 
 Lake Huron, 201, 367, 542; preglaclal out- 
 let of, 304 et seq.; glacial drainage of, 314, 
 317; origin of, 356, etseq. 
 
 Lake Humber, 448, 451, 452. 
 
 Lake Itasca, 655. 
 
 Lake Lahontan, 608 et seq., 612. 
 
 Lake Lesley, 156. 
 
 Lake Llndeman, 29. 
 
 Lake Michigan, 211, 306, 354, 361, 525, 528, 
 665; preglaclal outlet of, 305, 306; glacial 
 drainage of, 314; origin of, 356 et seq.; 
 dunes of, 545;po8t-glaclaler03ionin,571. 
 
 Lake Mlnnetonka, 211, 212, 361. 
 
 LakeMono, Cal.,273, 607. 
 
 Lake Nlplsslng, 542. 
 
 Lake Ontario, 148, 395, 398, 536, 587; pre- 
 glaclal drainage of, 304 et seq. ; origin of, 
 356 et seq. 
 
 Lake ridges, around Erie, 395, 397; around 
 Ontario, 395. 
 
 Lake Superior, 199, 201, 212, 213, 325, 367, 
 528, 664; preglaclal outlet of, 305, 306; 
 glacial drainage of, 314; origin of, 356 et 
 seg, ; vicinity of, acenter of snow-fall, 527. 
 
 Lake Traverse, 316, 354. 
 
 Lake Washington, 181. 
 
 Lake Williams, 153, 154. 
 
 Lake Wlnnepesaukee, 221, 363. 
 
 Lake Winnipeg, 654, 655. 
 
 Lakes formed in mountain-building, 510, 
 512. 
 
 LamoUe River, 347. 
 
 Lamplugh, G. W., 505, 587. 
 
 Lang, Mr. C, 105. 
 
 LaPdrouse, 42, 43. 
 
 Lattas, Ohio, 602. 
 
 Laurentlan lakes, basins of the, 500, 501. 
 
 Laurentlan Mountains, 199, 244, 246, 259, 
 357, 527. 
 
 Lava-beds in western United States, 417. 
 
 ■ 418. 
 
 Lawrence county, Pa., 326. 
 
 Lawrence, Mass., 343, 350. 
 
 Lawrenceburg, Ind., 326, 327. 
 
 Le Conte, Professor Joseph, 498, 501, 507; 
 on succession of glacial epochs, 490; on 
 deep placer deposits In California, 688 
 et seq. 
 
 Lebanon Mountains, glaciers of, 612 et seq. 
 
 Lehigh River, 325, 637. 
 
 Lehigh Water-Gap, 197. 
 
 Lenox, Mass., train of bowlders In, 239, 240. 
 
 Lesley, Professor J. P., on depth of the ice, 
 195-197; on elevation of bowlders, 196, 248 
 et seq. ; on depth of drift In, 259 ; on erosion 
 in northern Pennsylvania, 260; on Cin- 
 cinnati Ice-dam, 371. 
 
 Lesquereux, Leo, on rate of accumulation 
 of peat, 594 et seq. ; cited, 690. 
 
 Leverett, Mr., on the Kanawha, 309; corre- 
 lates Alpine episode with American, 580; 
 on age of Kansan till, 588. 
 
 Lewis, Professor H. CarvlU, 619, 628, 629, 
 637; begins the survey of Pennsylvania, 
 135, 148, 149; discovers moraine on Pocono 
 Mountain, 147; on transportation of bowl- 
 ders, 197, 247 et seq.; on depth of ice in 
 eastern Pennsylvania, 197 ; on erosion In 
 northern Pennsylvania, 260; reports 
 drumllns In Pennsylvania, 287; on mar- 
 ginal kames in eastern Pennsylvania, 
 352; on glaciated area of Great Britain, 
 448, 449 et seq.; on kettle-hole at Free- 
 hold, Pa., 598; the Philadelphia red 
 gravel and brick-clay of, 637, 671. 
 Lewiston, Me., 343. 
 Licking county, Ohio, 169, 564, 603. 
 
754 
 
 INDEX. 
 
 Licking River, Ky., 310, 367, 385-387. 
 
 Licking River, Ohio, 300. 
 
 Llndenkohl, A., 502. 
 
 Little Falls, Minn, 619, 653 et seq. 
 
 Little Falls, N.Y., 329. 
 
 Little Miami River, 327, 643, 644, 645. 
 
 Little Sandy River, 19. 
 
 Little Scioto, 309. 
 
 Lltuya, 42, 43. 
 
 Lltuya Bay, Alaska, 74. 
 
 Llama, 436, 437. 
 
 Loess, 172, 256, 685; chapter on, 407-420; 
 Pumpelly on, 407, 408; composition of, 
 407, 412; in China, 408, 513; Baron Rlchtr 
 hofen on, 408; In Europe, 410, 512; in 
 America, 410; Hllgard on, 410, 411; alti- 
 tude of deposits of, 410, 413, 416; Cham- 
 berlln on, 412; theory of, 413 et seq., 588; 
 extent of subsidence indicated by, 413, 
 416; TJphara on, 415; earthworms and 
 the, 418; m Ohio, 644. 
 
 Logan, Sir William, 570. 
 
 Long Island, terminal moraine on, 140, 144, 
 204, 207; bowlders on, 238; over-wash 
 gravel on, 349; kettle-holes on, 360, 
 
 Long Level, W. Va., 381, 604. 
 
 Long, Mr., on Paint Creek, 562. 
 
 Lorain county, Ohio, 395. 
 
 Lorange, on cirques, 274, 276. 
 
 Louisville, Ky., 178, 300. 
 
 Loveland, Ohio, palseolithic implements 
 found at, 643, 645. 
 
 Lowell, Mass., 343-345. 
 
 Lubbock, Sir John, 624. 
 
 Luzerne county, Pa., 148. 
 
 Lycoming county. Pa., kettle-holes in, 149; 
 terminal moraine In, 149; bowlders In, 
 242. 
 
 Lycoming Creek, 149, 325. 
 
 Lyell, Sir Charles, 497, 509; observations 
 of. In Nova Scotia, 126,127; on Richmond 
 train of bowlders, 239, 240; theory of the 
 cause of the Glacial period, 495 ; principle 
 of uniformity, 533; on rate of recession 
 of Niagara Falls, 539, 706; on antiquity 
 of man, 616, 624. 
 
 Lynn Canal, Alaska, 27, 43, 59, 61, 188. 
 
 Machlas River, 342, 343. 
 Mackenzie River, 246. 
 Mackintosh, Mr., 570. 
 Macoun, Professor, cited, 569. 
 Madison, N. H., bowlder In, 238. 
 Madlsonville, Ohio, palseollthlc imple- 
 ments found at, 643, 644. 
 Magdalena Bay, 107. 
 
 Maine, 137, 441, 665; depth of Ice in, 194, 
 195; bowlders in, 247; depth of drift in, 
 259 ; absence of drumllns of large size in, 
 286; kames In, 349-351, 353; lakes In, 361; 
 marine beds overlying glacial drift, 504. 
 
 Malasplna Glacier, 30, 31, 32, 606. 
 
 Mammoth, 438, 586, 690. 
 
 Mammoth Cave, 229. 
 
 Man, antiquity of, in America, 438, 534, 
 639-640; and the Glacial period, chapters 
 on, 616-709. 
 
 Manchuria, 427, 432. 
 
 Mandan, 430. 
 
 Manitoba, 335, 354. 
 
 Manomet Hill, 139. 
 
 Marginal drainage, 175, 333 et seq., 351, 352. 
 
 Marietta, Ohio, 323, 327. 
 
 Marine shells, elevation of. In glacial de- 
 posits in Wales. 453; near Boston, 453. 
 
 Marr, Mr. J. E., on erosion in Greenland, 
 256, on glacial dams, 366. 
 
 Marshall, Ohio, 602. 
 
 Martha's Vineyard, 137, 144, 203, 237. 
 
 Martinsville, Ohio, 309. 
 
 Marvine Glacier, 32. 
 
 Mary Minturn River, 92. 
 
 Massachusetts, terminal moraines of, 137, 
 139; depth of Ice in, 195; depth of drift 
 in, 259; transported bowlders in^ 238, 
 239, 240; drumllns in, 283-285, 288; kames 
 in, 330, 353; kettle-holes in, 360, 361, 575; 
 lakes in, 361. 
 
 Mastodons, 436, 437, 586, 639, 645, 675, 690. 
 
 Mattawa River, 542, 543. 
 
 Mattawamkeag, Me., 343. 
 
 Mattawan, Can., 542, 543, 548. 
 
 Mattlson, Mr., 700, 701. 
 
 Mattmark, Sea, 365. 
 
 Maumee River, terminal moraine In valley 
 of, 207 et seq., 266. 
 
 McConnell, Mr. R. G., on the Cypress 
 Hills, 199, 200; on depth of drift in Brit- 
 ish America, 259. 
 
 MoGee, Mr. W J, 512; Columbia period 
 of, 613, 639, 671. 
 
 McKeesport, Pa., 379. 
 
 Medial moraines, east arm of Kettle Range, 
 a. 211 ; Coteau des Prairies, a, 214. 
 
 Medial moraines, formation of, 9; of Muir 
 Glacier, 43, 49, 236; of White River Glac- 
 ier, 22. 
 
 Mediterranean Sea, 433. 
 
 Medllcott and Blandf ord on signs of glac- 
 lation in India, 484, 485. 510. 
 
 Medora, Ind., palEeolithIc Implements 
 found at, 649 et seq. 
 
 Megalonyx, 436. 
 
INDEX. 
 
 755 
 
 Megatherium, 436. 
 
 Melville Bay, 92. 
 
 Mer de Glace of Switzerland, 3, 4, 10; of 
 Greenland 87, 89, 90. 
 
 Merjelen Sea, 364. 
 
 Merrimack River, 330, 331, 343, 344, 350, 
 660. 
 
 Mesozolc era, absence of glacial epochs 
 during the, 515, 518. 
 
 Metuchen, N. J., 142. 
 
 Metz, Dr. C. L., finds palEeollthlc Imple- 
 ments at Loveland and MadlsonvlUe, 
 Ohio, 619, 642, 644, 645. 
 
 Michigan, burled channel In, 306; salt 
 deposits of, 464. 
 
 Middle Bass Island, 262. 
 
 Migrations of plants and animals, 422, et 
 seq., 606, 513, 665. 
 
 Milan, Ind., 602. 
 
 MUk River, 334. 
 
 MlU Creek, 300, 301, 393, 643, 644. 
 
 Minneapolis, Minn., 211, 212, 303, 315, 
 361, 552, 554, 655, 660. 
 
 Minnesota, drlftless area of, 134; depth of 
 ice In, 201; terminal moraines in, 211-213, 
 525, 613, 655, 661 et seq.; varieties of drift 
 m, 213; depth of drift in, 258, 555; drum- 
 lins absent in, 287; waterfalls in, 303, 552 
 et seq.; delta terraces in, 334; occasional 
 kames in, 353; lakes of, 361 ; loess In, 416; 
 preglaclal man in, 438, 653 et seq. ; post- 
 glacial erosion in, 552 et seq. ; buried chan- 
 nel in, 553 et seq.; wells In, 555, 605, 607; 
 vegetable deposits in, 605; paleolithic 
 discoveries In, 619, 653 et seq. 
 
 Minnesota River, 214, 315, 316, 336, 354, 361, 
 
 M362, 554-556, 558, 559. 
 Ississlppl River, 136, 171, 203, 354, 357, 
 358, 361, 389, 417, 527, 634, 655, 656, 665; 
 preglaclal channels of, 311; preglaclal 
 erosion of, 228, 298, 315, 496; loess of the 
 valley of, 256, 410 e« seg. , 415 ; glacial drain- 
 age of, 313, 314; terraces on, 315, 415, 558, 
 654 ; post-glacial erosion in, 315, 552 e/ seg. , 
 665; rate of transportation by the, 562. 
 
 Missouri coteau in British America, 135, 
 176, 217 ei seq. ; source of, 244. 
 
 Missouri coteau in Dakota, 215, 217, 332, 
 333. 
 
 Missouri, glacial boundary in, 172, 415; 
 bowlders in, 243. 
 
 Missouri River, 172-175, 215, 220, 243, 244, 
 320, 321, 336, 414-416. 
 
 Mohawk River, 195, 228, 303, 305, 314, 319, 
 352, 353, 587; Ice-dam in, 398, 536, 539. 
 
 Mohawk Valley, 542. 
 
 Mohegan Rock, Conn., 238. 
 
 Mono county, Cal., 13, 222. 
 
 Monongahela River, 300, 308, 370, 372, 377, 
 378, 384, 604; loe-dam In, 391-393. 
 
 Monroe county. Pa., terminal moraine In, 
 146, 148; depth of Ice In, 195, 198; burled 
 channels In, 311. 
 
 Montana, former glaciers In, 13, 176;glaclal 
 boundary In, 133, 175; bowlders In, 243. 
 
 Mont Blanc, 104, 109. 
 
 Montgomery county, Ohio, organic re- 
 mains in glacial deposits In, 592, 593; 
 depth of till In, 592. 
 
 Montreal, marine beds overlying glacial 
 drift, 504; depression at, 542. 
 
 Moose, 675. 
 
 Moraines, formation of, described, 9. 
 
 Moraines of retrocession, 57, 207, 222, 223. 
 
 Moreau River, 174, 175. 
 
 Morgan county, Ind., 601. 
 
 Morgantown, Ind., 601. 
 
 Morgantown, W. Va., 370, 377, 378, 603. 
 
 Morris county, N. J., 241. 
 
 Morrison county, Minn., 653, 655. 
 
 Morse Glacier, 72. 
 
 Moulins defined, 9; on Mount Tacoma, 22; 
 on Mulr Glacier, 48. 
 
 Mountaln-buUdlng, probably correlated 
 with epochs of glaclatlon, 499, 502, 507, 
 509 et seq. 
 
 Mount Baker, 23, 180, 192. 
 
 Mount Crillon, 42, 43, 68. 
 
 Mount Dana, 15. 
 
 Mount Desert, Me., 137, 194, 195. 
 
 Mount Falrweather, 35, 42, 43, 68. 
 
 Mount Hood, 19, 192. 
 
 Mount Jefferson, 19. 
 
 Mount Katahdln, Me., 195, 247, 348, 441. 
 
 Mount Kelertingouit, Greenland, 85, 86. 
 
 Mount McKlnley, 36. 
 
 Mount Lyell, 15, 269, 273. 
 
 Mount Rainier. See Mount Tacoma. 
 
 Mount Shasta, 15 et seq., 192. 
 
 Mount St. Ellas, 30, 34-36, 42. 
 
 Mount Tacoma, 21, 136, 180, 192, 193. 
 
 Mount Washington, 194, 246, 439-441. 
 
 Mount Wrangel, 36. 
 
 Mower county, Minn., 605. 
 
 Mud Hiver, W. Va., 381. 
 
 Mulr Glacier, cross-section of, 4, 39; kames 
 forming in, 11, 66, 342; discovery of, 39; 
 chapter on, 40-74; accessible to tourists, 
 40; difficulties of measurement, 41, 52;. 
 surrounding mountains, 41-43; vegeta- 
 tion in the vicinity of , 41 , 67 ; view of , 42 ; 
 former extension of, 43, 59, 189; relation 
 to Glacier Bay , 45 ; width of , 45 ; terminal 
 moraine of, 45, 57; transported bowlders 
 
756 
 
 INDEX. 
 
 on, 45, 236; thickness of, 47, 234; slope of, 
 47; extent of, 47; moulins of ,48; nunataka 
 of, 47, 79, 189; medial moraines of, 43, 49, 
 56, 236; loe-plllars of, 49; surface of, 50; 
 front of, 50; icebergs from, 50, 51, 67; 
 subglacial streams of, 51, 55, 57, 61, 66 et 
 &eg_., 342; burled forests near the, 53, 61 
 et seq., 233, 592; velocity of, 55, 80; dally 
 discharge of , 55, 82 ; view of surface of, 56 ; 
 kettle-holes In front of, 57, 58, 66, 144, 204 ; 
 retreat of, 57; former extent of, 59; Van- 
 couver on, 59; view of stumps of cedar 
 trees 62, 63; movement over gravel de- 
 posits, 66, 233; sediment, 68 ; temperature 
 near, 69; Professor Reld on, 71, 72. 
 
 Mulr Inlet, 41, 45, 189, 192; list of plants 
 about, 69. 
 
 Muir, Professor, explorations In Alaska, 
 39, 68. 
 
 Muskingum River, 300, 314, 323, 327. 
 
 M>isk-ox, 675. 
 
 Mylodon, 436. 
 
 Naaman's Creek, 675. 
 
 Nampa image, 701 et seq. 
 
 Nansen, Dr. F., on Greenland, 98. 
 
 Nantlooke, Pa., 332. 
 
 Nantucket, 137, 139,203. 
 
 Natal, Permian glacial deposits in, 516. 
 
 Naushon, 204 et seq. 
 
 Nebraska, glacial boundary In, 172; bowl- 
 ders in, 243; loess In, 411, 414, 415, 587. 
 
 Nelson River, 313. 
 
 Nevada, former glaciers in, 176; salt lakes 
 In, 607. 
 
 NH6 field, in Greenland, 88; on the Sierra 
 Nevada, 18, 179, 273 
 
 New Alexandria, Ohio., 168. 
 
 Newark, Ohio, 169, 326. 
 
 Newberry, J. S., 487; on glaciers of Cascade 
 Range, 19; on depth of glacial deposits, 
 257; on glacial erosion, 261 ; on formation 
 of the Great Lakes, 262, 356 et seq.-. on 
 buried channels In Ohio, 300, 301 ; on pre- 
 glaclaldralnage throu^Ontario, 305,306. 
 
 New Burlington, Ohio, 602. 
 
 Newbury port, Mass., 343. 
 
 Newcomb, Professor Simon, 192, 476. 
 
 Newcomerstown palseollth, 645 et seq. 
 
 New England, 139, 358, 398, 487, 523; glacial 
 drainage of, 136; kettle-holes In, 139, 360, 
 361; depth of Ice In, 194, 195, 201; termi- 
 nal moraines of, 134, 203, 361 ; transpckrted 
 howlders in, 237, 238, 239, 240; depth of 
 drift in, 259; glacial drainage In, 330, 331, 
 342, 343; kames In, 330, 343 el seq.; lakes 
 In, 361, 363; peat-bogs, 360. 
 
 NewHamp3hire,139,665;depthofIcein,194 
 transported bowlders in, 194, 237, 246; 
 terminal moraines in, 221; depth of till 
 in, 259; drumllns in, 283, 285, 288; delta 
 terraces In, 330; kames In, 340, 341; lakes 
 in, 361, 363, 
 
 New Harmony, Ind., 170, 326. 
 
 Ne>v Jersey, terminal moraine in, 133, 134, 
 140, 142, 144, 151, 206; depth of Ice in, 198; 
 transported'bowlders in, 241 ; lakes in, 363 ; 
 interglaclal man in, 438.; palaeolithic dis- 
 coveries in, 619, 620, 625 e( seq. 
 
 New Mexico, 274. 
 
 New Richmond, Ohio, 367. 
 
 New York, 317, 398, 665; glacial boundary 
 in, 133, 525; depth of Ice in, 195, 261; ter- 
 minal moraine in, 149, 206; bowlders in, 
 242; drift hills In, 286; buried channels 
 in, 305, 306, 307, 308; kames in, 352, 353; 
 lakes In, 363; lake ridges In, 395; salt de- 
 posits in, 463. 
 
 New York Central Railroad, terraces 
 along the, 329. 
 
 New York City, 357, 398, 502. 
 
 New Zealand, glaciers In, 104, 112, 488, 510; 
 cirques In^ 274. 
 
 Niagara gorge, length of, 299, 353, 376, 536; 
 a glacial chronometer, 299, 536 et seq., 
 548-552; erosion of, 542; recession of at 
 standstUl, 543. 
 
 Nlles, Professor, on erosion by the Aletsch 
 Glacier, 231, 232. 
 
 Nlobraia River, 172. 
 
 Nlsqually River, 21. 
 
 Nittany Valley, Pa., 229, 230. 
 
 No Man's Land, 137. 
 
 Nordenskiold, A. E., 518; on influence rtf 
 meteoricdaist,9 ;e»pedltlon to Greenland, 
 75 et seq. ; on subsidence of Sahara, 433. 
 
 Northampton county. Pa., terminal mor- 
 aine is, 146. 
 
 Nort^ Bass Island, 262. 
 
 North Bay, Can., 548. 
 
 North Bend, Ohio, 170, 367. 
 
 North Carson Lake, Nevada, 607. 
 
 Northern Pacific Railroad crosses the gla- 
 cial boundary, 174, 175, 213. 
 
 North Sea Glacier, 446, 449. 
 
 Norway, glaciers of, 104, 106, 110, 232, 234, 
 445; erosion in, 278 ; depth of ice in, 447. 
 
 Nova Scotia, 126, 127; absence of Quater- 
 nary marine beds In, 504. 
 
 Nova Zembla, 107, 488. 
 
 Nunataks, 47, 79, 189, 254, 366. 
 
 Oahe, Dakota, 174. 
 Oberlln, Ohio, 565. 
 
INDEX. 
 
 Ihl 
 
 Ocean lowered to supply Ice, 503 ; raised by 
 ice attraction, 503. 
 
 Ohio, fringe In, 167; terminal moraine In, 
 168 et aeq., 198, 372; kettle-holes In, 168, 
 169; wells In, 168, 169, 257, 268, 602; bowl- 
 ders In, 242, 243 ; depth of tUl In, 257, 258, 
 
 592, 593, 598-600; preglaclal erosion In, 
 299, et seq. ; burled channels In, 300 et seq., 
 304, 644; glacial drainage In, 314; absence 
 of terraces In unglaclated part, 323; 
 kames In, 353; limit of glacier In, 357, 
 358; glacial erosion In, 358; glacial 
 boundary in, 367, 525, 526; lake ridges 
 In, 395 et seq. ; Interglaclal man In, 438, 
 640 et seq.; post-glacial erosion in, 560; 
 strlse In, 691; vegetable deposits in, 692, 
 
 593, 598 etseq., 602, 603; loess In, 644; 
 palseolithlG Implements In, 642 etseq. 
 
 Ohio River, 170, 208, 228,353, 358, 634, 643; 
 glacial drainage of, 314, 353; preglaclal 
 drainage of, 309, 310; occupies a pregla- 
 clal gorge, 299 et seq., 384; glacial dam 
 in, 366, et seq; terraces on, 370 et seq. 
 
 Oil Creek, Pa., 326. 
 
 Okhotsk-Kamchatkan region, flora of, 
 441-444. 
 
 Olympian Mountains, 180, 192. 
 
 Ontario, Can.. 665. 
 
 Oregon, 222, 417, 426; glaciers in, 19, 177, 
 191, 192, 607. 
 
 Ot^gonla, O., limestone bowlder In, 239. 
 
 Orton, Professor Edward, on bowlder at 
 Oregonla, 0., 239; on depth of till, 257; 
 on burled channels in Ohio, 302; on 
 Paint Creek, 560; on vegetable deposits 
 In Ohio, 592, 602. 
 
 Osage River, 321. 
 
 Oscillations of land and sea, 497 et seq. 
 
 Osslpee Lake, 351. 
 
 Ottawa Valley, 542, 543. 
 
 Over-wash gravel, 204, 348 et seq. See 
 Delta Terraces and Kames. 
 
 Owen, Miss, finds Implement at St. 
 Joseph, Mo. 
 
 Oxford, Ohio, 600. 
 
 Oysters, 586. 
 
 Packard, Prof. A. S., 504; reports trans- 
 ported bowlders on Mount Katahdln, 
 Me., 247. 
 
 Paint Creek, 326, 372 «« aeq., 384, 660 et seq. 
 
 Palsolltbs., characteristics of, 616 et seq.; 
 Haynes on, 619 et seq.; oceurrence of, 
 in glacial gravels in France and England, 
 623-625; at Trenton, N. J., 626 et seq.; at 
 Madlsonvllle and Loveland, Ohio, 642 
 et aeq.; at New Comerstown, Ohio, 645 
 
 et seq.; at Medora, Ind., 649 et seq.; at 
 Little Falls, Minn., 653 et seq.; at Clay- 
 mont, Del., 669 et seq. 
 
 Palestine, Ohio, 168. 
 
 Panama, Isthmus of, Quaternary oscil- 
 lations of, 568. 
 
 Paris Crossing, Ind., 602. 
 
 Parker Creek, 15. 
 
 Parker, Pa., 604. 
 
 Passadumkeag, Me., 343. 
 
 Patagonia, 104, 488. 
 
 Patterson Glacier, 27. 
 
 Patton, Rev, J. L., 40. 
 
 Payer, Mr., on east coast of Greenland, 
 98. 
 
 Peabody Bay, 92. 
 
 Peary, R. A., 99, 100. 
 
 Peat-beds, formation of, 360, 594 et aeq.; 
 ageof , 573, 574, 597, 598; in New England, 
 360 ; In southern Ohio, 592, 593 ; in Penn- 
 sylvania, 698; in Minnesota, 605. 
 
 Peekopee Lake, 334. 
 
 Pelee Island, 262. 
 
 Pelican Lake, 334. 
 
 Pembina River, 333, 334. 
 
 Penck,Dr. A., on cirques, 275, 278; on Al- 
 pine glaciers, 459; on oxidization, 580. 
 
 Pendelton county, Ky., 170. 
 
 Pennsylvania, 436, 487; terminal moraines 
 m, 133, 146 et aeq., 206, 376, 526; kettle- 
 holes In, 148, 598 ; fringe in, 153, 167 ; trans- 
 ported bowlders In, 241, 242; terraces in, 
 150, 370-372, 375, 379, 384; depth of ice in, 
 196 et seq.; direction of strlse in, 248, 249; 
 depth of till in, 259; glacial erosion in, 
 260; wells In, 260,604; few drumllns In, 
 287; buried channels in, 307, 308, 332; 
 kames In, 348, 352; marginal drainage In, 
 352; vegetable deposits In, 604. 
 
 Penobscot River, 342, 343. 
 
 Perclval on drumllns, 286. 
 
 Permian glacial epochs, 484, 4S6, 609, 615, 
 618. 
 
 Perry county, Ohio, 169, 326. 
 
 Perth Amboy, N. J., 140. 
 
 Perthes, Boucher de, palsollthic discover- 
 ies of, in France, 574, 623, 624. 
 
 Peru, post-glacial elevation of, 507. 
 
 Petermann Peak, 98. 
 
 Philadelphia, 671; and vicinity, preglac- 
 lal elevation of, 502. 
 
 Philadelphia red gravel and brick-clay, 
 634 et aeq., 636, 671, 673. 
 
 Pickaway county, Ohio, 169. 
 
 Pike county, Ohio, 372 et seq., 374. 
 
 Pike county, Pa., 205. 
 
 Pilgrim Fathers, 137. 
 
758 
 
 INDEX. 
 
 Pipestone county, Minn., 353. 
 
 Plscataqua Elver, 342, 352. 
 
 Pittsburgh, Pa., 370, 375, 384. 
 
 Plalnfield, N. J., 140, 142. 
 
 Plains, the Western, uplifted in the Qua- 
 ternary period, 502. 
 
 Plants, in the clay deposits of the Monon- 
 gahela, 392; migrations of, diu-lng the 
 Glacial period, chapter on, 422-444; pre- 
 glacial distribution of, 422, 430 ; Professor 
 Asa Gray on, 422 ei seq. ; resemblance of, 
 in Japan and eastern North America, 
 423, 432; manner of migration of, 424; of 
 the Pacific coast of North America, 426, 
 435; of Japan and North China, 427, 434; 
 of Europe, 427; of the Tertiary period, 
 
 428, 430; effect of Glacial period upon, 
 
 429, 431, 433; the birthplace of, 432; on 
 oceanic Islands, 436; list of, common to 
 the Okhotsk-Kamchatkan region and 
 North America, 441-444. 
 
 Platte Blver, 172, 177, 414, 416. 
 
 Plum Greek, Ohio, 565-568, 575. 
 
 Plum Island, 140. 
 
 Plymouth county, Mass., 137, 139, 360. 
 
 Plymouth Rock, Mass., 238. 
 
 Pocatello, Idaho, 337. 
 
 Pocono Mountain, terminal moraine on, 
 133, 146, 148, 526; depth of ice over, 198; 
 bowlders on, 241. 
 
 Pohlman, Dr., on the Niagara gorge, 540. 
 
 Point Pleasant, Ohio, 36. 
 
 Point Wilson, state of Washington, 182.' 
 
 Polar loe-cap, 179, 192. 
 
 Pomp's Pond, Andover, Mass., 572 et eeq. 
 
 Port Foulke, 89, 92. 
 
 Port Jervis, 314. 
 
 Port Townsend, 180, 182. 
 
 Portland, Me., 349. 
 
 Portland, Ore., 21, 39, 40, 135. 
 
 Portland, Pa., 352. 
 
 Post-glacial erosion, 590; in gorge of Niag- 
 ara, 269, 536 el seq.; of Mississippi, 315, 552 
 et seq.; of Paint Creek, 561, 562; In Rac- 
 coon Creek, Ohio, 564, 565; In Plum 
 Creek, Ohio, 565-568; In Lake Michigan, 
 571. 
 
 Post-glacial oscillations of level, 504-506. 
 
 Pot-holes, in Grafton county, N. H., 331; 
 In Lackawanna county. Pa., 332; at Mat- 
 tawan. Can., 543. 
 
 Potomac River, 671. 
 
 Potter county. Pa., terminal moraine In, 
 149;depthof Icein, 195. 
 
 Powell, Major J. W., 498. 
 
 Pratt, Archdeacon J. H., 497. 
 
 Precession of equinoxes, 467, 468, 509, 511. 
 
 Preglacial climate, 463. 
 
 Freglaclal drainage, chapter on, 298-312; 
 lower levels of. In the Ohio Valley, 300 
 et seq. ; erosive effect of , 300 ; buried chan- 
 nels of, 301 et seq. ; in the vicinity of Cin- 
 cinnati, 301; In central Ohio, 302; In the 
 vicinity of Minneapolis, 303; between 
 Lakes Erie and Ontario, 303 ; In southern 
 tributaries to Lake Erie, 304; between 
 Lakes Huron and Ontario; 304; in the 
 Mohawk Valley, 305; In nilnois, 306; In 
 western Pennsylvania and western New 
 York, 307, 308; In eastern Pennsylvania, 
 311; In the Province of Quebec, 312. 
 
 Preglacial elevation, 502. 
 
 Preglacial erosion, extent of, 226 et seq:, 261, 
 279, 298 et seq., 353, 540, 542, 562, 564. 
 
 Preglacial terraces, 372. 
 
 Preglacial topography, 590. 
 
 Freglaclal weathering of strata, 513. 
 
 Prehistoric wooden structures of Naaman's 
 Creek, 675. 
 
 Prestwlch, Professor Joseph, 498, 511, 514, 
 617, 624; on length of Glacial period, 613 
 et seq. 
 
 Prince William Sound, 36. 
 
 Provlncetown, Mass., 137. 
 
 Puget Sound, 136, 176, 180, 192, 193. 
 
 Pumpelly, Professor Raphael, 513, 517; on 
 preglacial erosion, 261, on loess, 407 et 
 seq. 
 
 Putnam county, W. Va., 379, 604. 
 
 Putnam, Professor F, W., 642; on his dis- 
 coveries of palseollthlc Implements, 627; 
 on antiquity of man in California, 698, 
 699. 
 
 Puyallup River, 21. 
 
 Pyramid Lake, Nev., 607. 
 
 Pyrenees, 429, 433, 436, 449 ; ancient glaciers 
 In, 512. 
 
 Qu'Appelle Elver, 333, 335. 
 
 Quebec, Province of, 570. 
 
 Queechee, Vt., 247. 
 
 Queen Charlotte Islands, 506. 
 
 Queen Inlet, 73. 
 
 Queenston, Can., 536 et seq., 550. 
 
 Raccoon Creek, Ohio, 324, 564, 575, 603. 
 Ramsay, Sir A. C, theory of rock baains, 
 
 269; on early glaclatlon, 483 et seq. 
 Randolph, N. Y., 149. 
 Eangeley Lakes, 342, 349. 
 Eavenna, Ohio, 353. 
 Eead, Mr. M. C, on burled channels In 
 
 Ohio, 301. 
 
INDEX. 
 
 759 
 
 Recession, rate of, o£ falls of Niagara, 536 
 et SCI]. ; Falls of St. Anthony, 552 et seq. ; 
 falls in Black River, Ohio, 560; of trib- 
 
 . utary to Paint Creek, 561, 562. 
 
 Red Bank, Ohio, 644. 
 
 Red River of the North, 199, 220, 258, 316, 
 333, 334, 354, 361, 607, 654. 
 
 Red River Valley, 548. 
 
 Retd, H. F., 71, 72. 
 
 Reld Glacier, 73. 
 
 Reid Inlet, 73. 
 
 Reindeer, 641, 675. 
 
 Rendu Glacier, 73. 
 
 Rensselaer Harbor, 89. 
 
 Revillo Gigedo Island, 188. 
 
 Rhine River, 410, 412, 447. 
 
 Rhinoceros, 586, 690. 
 
 Rhode Island, terminal moraine in, 140, 
 204; depth of drift in, 259. 
 
 Rhone Glacier, 255. 
 
 Richardson , Mr. James, 187, 188. 
 
 Richardson, Sir J., on transported bowf- 
 ders in the Mackenzie Valley, 246. 
 
 Richmond, Mass., train of bowlders in, 
 239-241. 
 
 Richthofen, Baron, 513, 517; on loess, 408, 
 409. 
 
 Ricketts, Dr. Charles, 508. 
 
 Rlggs, Rev. Thomas L., 175. 
 
 Rink, H., on results of Greenland explor- 
 ation, 77 eiaeg. 
 
 Ripley county, Ind., 602. 
 
 Ripley, Ohio, 170, 367, 526. 
 
 River that turns, 335. 
 
 Rivldre des Lacs, 334. 
 
 Roches moutonnfes, 84, 183, 185, 187, 227, 
 231, 295, 483. 
 
 Rook-baslna in the Sierra, 267 et seq., 365. 
 
 Rock-scoring in Glacier Bay, Alaska, 44; 
 described, 12Setseq.; near Victoria, Van- 
 couver Island, 183 et seq.; on Islands in 
 Lake Erie, 262 etseq.; on the Sierra, 267 
 et seq.; In South Africa, 485. 
 
 Rocky Mountains, 13, 14, 200, 244, 273, 
 415-417, 429, 441 , 462,' 607 ; ancient glaciers 
 In, 175-177, 512; Quaternary uplifts of, 
 502, 507, 511, 512. 
 
 Rocky River, 304. 
 
 Rome, N. Y., 542, 587. 
 
 Ross county, Ohio, 372; terminal moraine 
 In, 169, 170; transported bowlders In, 169, 
 242; vegetable deposits In, 602. 
 
 Ross, Sir J. C, explorations of, In Ant- 
 arctic Continent, 112 et seq. 
 
 Russell, Mr. I. C, on glaciers of the Sierra 
 Nevada, 179; on moraines of Monocoun- 
 ty, Cal., 222; on glacial erosion, 267; on 
 
 Yosemlte Valley, 271; on cirques, 271 el 
 seq. ; on Lakes Lahontan and Bonneville, 
 608, 610; on gravel deposits about Dead 
 Sea, 612. 
 
 Russell Fiord, 31, 32. 
 
 Sabine, E., explores east coast of Green- 
 land, 98. 
 
 Saco River, 221, 342, 351. 
 
 Saguenay, fiord of the, 501. 
 
 Sahara, Desert of, 433, 496. 
 
 Salamanca, N. Y., 586. 
 
 Salisbury, Professor R. D., 501; on loess, 
 172; discoveries In northern Germany, 
 452,456; on deposits in New Jersey, 636. 
 
 Sandusky, Ohio, 262, 390. 
 
 Sandy River, 19. 
 
 Saskatchewan River, 13, 199, 220, 244, 259, 
 333 et seq., 526, 545. 
 
 Sawklns, J. G., 507. 
 
 Soarboro Heights, 584, 685, 587. 
 
 Scandinavia, glaciers of, 104, 106, 445, 447; 
 erosion In, 260; maximum post-glacial 
 uplift, 506. 
 
 Schenectady, N. Y., 329. 
 
 Schoodlc Lake, 350. 
 
 Schoolcraft on the antiquity of man, 699. 
 
 Schuylkill Water-Gap, 197. 
 
 Schwatka, F., explorations in Alaska by, 
 29, 30, 190. 
 
 Scioto River, 169, 300, 314, 323, 326, 327, 375, 
 561. 
 
 Scoresby explores east coast of Greenland, 
 98. 
 
 Scotland, 487, 534; glacial erosion In, 278 ; 
 kames in, 339; glaclatlon in, 445, 446, 483, 
 484; post-glacial erosion in, 568; maxi- 
 mum post-glacial uplift, 506. 
 
 Scott, Captain, 120. 
 
 Scratched stones, by moving Ice, 125 et seq. ; 
 by land-slides, 127. 
 
 Sorlbner, Mr., 701. 
 
 Scudder, Mr. Samuel, on the existence of 
 Alpine insects on the White Mountains, 
 438, 439. 
 
 Sea cow, 436. 
 
 Sea-level, changes of the, 503. 
 
 Seattle, State of Washington, 21, 135, 180- 
 182. 
 
 Second Glacial epoch, 207, 258, 558, 575, 579, 
 601, 669. 
 
 Seeman, G. B., visits Kotzebue Sound, 37. 
 
 Selkirk Mountains, glaciers in, 13. 
 
 Serrate character of glacial margin, 132, 
 525 et seq. 
 
 Seville, Ohio, 353. 
 
 Seymour, Ind., 601. 
 
 Shackelton, E., 120, 121, 
 
760 
 
 INDEX. 
 
 Staler, Professor, N. S., 498-500; on depth 
 of tlie drift In New England, 259; on 
 drumllns, 288, 290; on glacial action In 
 the Connecticut Valley, 486; In Appala- 
 chian region, 487; on the Trenton 
 gravel, 630. 
 Shawshln River, 338. 
 Sheep, 436. 
 
 Sheyenne River, 333, 334. 
 Shingle Creek, 553, 554. 
 Ship-canal, possible, between Lakes Su- 
 perior and Michigan, 306. 
 Ship Rock, Mass., 237. 
 Siberia, 36, 476, 477, 479. 
 Sierra Nevada Mountains, 409, 429, 607, 
 611 ; glaciers in, 13 el aeq., 177, 179, 180, 273 ; 
 rock-^basins in, 267 et seq. ; cirques In, 272 
 et seg.;Quaternary uplifts of the, 501, 502, 
 ,507; glaclatlon of, 568; erosion of, 569. 
 Sinclair, Professor W. J., 700. 
 Slnlan MoTintain system, 517. 
 Sink-holes, frequent In limestone regions, 
 
 143. 
 Sitka, Alaska, 68, 189. 
 Skeena River, 25. 
 Slickenslde, 129. 
 Smith Sound, 86, 92, 245. 
 Smock, Professor J. C, on depth 'Of ice In 
 
 New Jersey and Pennsylvania, 198. 
 Somme River, 574, 623, 624. 
 Sourls River, 334. 
 Southall, J. C, 508; on antiquity of man in 
 
 California, 697, 698. 
 South Amerlca,437,47S;glaciers of, 104, 108 
 et seq,, 462; relation of contour of, to the 
 Gulf Stream, 472, 473. 
 South Bass Island, 262, 266. 
 South Brewster, Mass., 139. 
 South magnetic pole, 121. 
 Spencer, Professor J. W., on the erosive 
 power of glaciers, 232, 233; on preglaclal 
 drainage, 302, 304; on St. Davids, 550. 
 Sperry Glacier, 13. 
 Spltzbergen, 104, 107, 424, 430, 463. 
 Split Rock, Ky., 385, 386. 
 Springfield, Ohio, 302. 
 Squler, Mr., 385. 
 Stainmoor Glacier, 449-451. 
 Stark county, Ohio, 169, 326. 
 Staten Island, 140. 
 
 St. Davids, Ontario, 537 et aeq., 549, 550. 
 Steenstrup, K. J. V., on rate of movement 
 
 of Greenland glaciers, 80. 
 Stickeen River, 25, 27, 136, 228. 
 St. Joseph River, Ohio, 208, 209. 
 St. Lawrence River, 305, 314, 354, 357-359, 
 
 St. Louis, Mo., 134, 171, 315, 591. 
 St. Marie's River, 208, 209. 
 Stockbridge, Mass.. train of bowlders in, 
 
 239, 240. 
 Stone, Professor George H., on moraines In 
 Maine, 221; on depth of drift in Maine, 
 259 ; on drumllns in Maine, 286; on kames 
 in Schoodlc Lake, Me., 350, 351. 
 St. Paris, Ohio, 257, 258, 302. 
 St. Paul, Minn., 315, 553, 554, 655, 660. 
 Strait of Georgia, 186, 188, 192. 
 Strait of Juan de Fuca, 182, 192. 
 Straits of Magellan, 111. 
 StrisB, direction of, on the west coast of 
 North America, 183, 186 et seq. ; in Maine, 
 195; on Hudson Strait, 246; in Western 
 Pennsylvania, 248, 249; in Lake Erie, 
 265, 266; in Scandinavia, 446; In India, 
 484 ; In Ohio and Indiana, 591 ; in Illinois, 
 591, 592. 
 Stroudsburg, Pa., 146, 352, 637. 
 Sub-Aftonian till, 224. 
 Subglaclal streams, source of, 82; of the 
 Alps, 18, 255; on Mount Shasta, 18; 
 Mount Hood, 19; Mount Tacoma, 21; 
 milky-white color of, 18, 21, 135, 136,254; 
 of Mulr Glacier, 51, 55, 62, 67, 68, 342; of 
 Greenland, 82, 255, 256; transporting 
 power of, 67, 68, 82, 135, 136, 254 et seq. 
 Submergence during the Glacial epoch In 
 North America, 200, 413; in Wales, 453. 
 Subsidence in Rocky Mountain region, 
 200 ; theory of, to account for lake ridges, 
 397, 398; necessary to account for loess 
 413; theory of, 413, 416; due to weight of 
 Ice-sheet, 416, 417, 497, 600, 510, 519; of 
 Sahara and central Asia, 433; on the 
 Atlantic, north of glacial limit, 635; in 
 Vermont, 635; In Dominion of Canada, 
 635; general, of the glaciated area, 591; 
 In the Delaware Valley, 636-640. 
 Sullivan county. Pa., 195. 
 Superglaclal streams, 22, 48, 75, 90. 
 Susquehanna River, 133, 136, 148, 198, 228, 
 
 241, 325, 352. 
 Sverdrup, Lieutenant, on east coast of 
 
 Greenland, 98. 
 Sweden, 104, 339; chalk bowlder in, 239. 
 Switzerland, 463, 496; erosion in, 231, 232, 
 274; glaciers of, 445, 448. 
 
 Table Mountain, 692; relics from 694. 
 
 Tacoma, 136. 
 
 Taku Inlet, 27. 
 
 Tapir, 436, 437, 690. 
 
 Tarr, Ralph, 32, 605. 
 
 Taylor, Mr., 543. 
 
INDEX. 
 
 761 
 
 Teazes Valley, 300, 379 et seg., 604. 
 
 Temperature, of the southern hemisphere 
 lower than that of the northern, 475; of 
 the Interior of South America, 478; of 
 northeast Siberia, 478; not altogether 
 dependent on the heat from the sun, 
 477; variations of, in different latitudes 
 not understood, 479 ; causes afifecting, 480. 
 
 Tennessee, conglomerates in, 487. 
 
 Terminal moraines, 251 ; conditions favor- 
 ing the formation of, 135, 203; char- 
 acteristics of, 142; on Nantucket and 
 Martha's Vineyard, 137,203;ontheEliza- 
 beth Islands, 137, 203; in Plymouth 
 county, Mass., 139; In Long Island, 140, 
 204; In New Jersey, 142, 151, 206; in east- 
 ern Pennsylvania, 144 et seq., 206; on 
 Pocono Mountain, 146; in Valley of Fish- 
 ing Creek, 148; in valley of Conewango 
 Creek, 150; in Ohio, 168 et seq., 207 et seq. ; 
 In Dakota, 174; In Washington State, 
 180; In Wisconsin, 211; south of 
 Maine, 195; south of New England, 203; 
 m central New York, 206; In Ammonoo- 
 suc Valley, 221; in Great Britain, 448 
 et seq.; in Germany, 447, 456; compared 
 with those of America, 456 et seq. ; lobate 
 contour of, 132, 207, 628, 530, 661. 
 
 Terraces, glacial, on the Conewango, Ohio, 
 150; at Lewlston, Pa., 155; on the Mo- 
 hawk, 319; on the St. Croix, 319; on the 
 Wabash, 319; on the Mississippi, 315, 
 415, 567, 654; on the Ohio and Its tribu- 
 taries, 323, 370 et seq.; in western Penn- 
 sylvania, 371; on Brush Creek, Ohio, 
 372; at Bellevue, Pa., 375, 384; near Mor- 
 gantown, W. Va., 377 et seq., 603; at 
 Clarksburg and Weston, W. Va., 378; at 
 McKeesport, Pa., 379; In Teazes Valley, 
 W. Va., 379 et seq., 604; on the Big Sandy, 
 W. Va., 382; and Guyandotte, 382; on 
 Lake Agassiz, 500, 655, 664; on the Min- 
 nesota, 558; on the White, Ind., 601; on 
 Kaccoon Creek, Ohio, 603 ;on the Somme, 
 France, 623, 624; in southern England, 
 624, 625; on the Delaware, 633 et seq., on 
 the Little Miami, 646. 
 
 Tertiary era, absence of Glacial epochs 
 during the, 515, 518. 
 
 Thames River, 447, 449. 
 
 Thibet, Quaternary uplift of, 510, 513, 
 
 Thompson, Mr. Gilbert, on the glaciers of 
 Mount Shasta, 15. 
 
 Thomson, Sir William, 497. 
 
 ThornviUe, Ohio, 169. 
 
 Three Sisters, 19. 
 
 Tidioute, Pa., 30;. 
 
 Tlerra del Fuego, 109, 110. 
 
 Tight, Professor, on Kanawha drainage, 
 309; on Middle Ohio drainage, 309. 
 
 Till, defined, 123, 129 e< seg.; depth of, 257, 
 et seq.; British Columbia, 185; In Minne- 
 sota, 213, 258, 555, 605, 607; In Canada, 
 258; In Indiana, 257, 601,602;In Illinois., 
 257; In Ohio, 257, 258, 592, 593, 599, 600; 
 In New England, 259; in Pennsylvania, 
 259, 260, 604; In Europe, 260; average in 
 North America, 280. 
 
 Tioga county. Pa., 195. 
 
 Titusvllle, Pa., 326. 
 
 Todd, Professor J. E., on glacial dams 
 across the Kansas and Platte River, 
 172 ; on Coteau des Prairies, 214 ; Missouri 
 coteau, 216, 217; on glacial drainage, 332. 
 
 Tonawanda Creek, 542. 
 
 Topeka, Kan., 172. 
 
 Toronto, Can., 584, 585, 586. 
 
 Torsukatak Glacier, 78. 
 
 Towson, Mr., 117, 118. 
 
 Trade-winds, motions of. In the Atlantic, 
 470; relations to the Gulf Stream, 472; 
 cause of the predominance of the south- 
 east, 473 et seq. 
 
 Transportation by subglaclal streams, 136, 
 136, 264 et seq.; in Alaska, 67, 68, 136; In 
 Greenland, 82, 256; In the Alps, 264, 256. 
 
 Transportation of bowlders, 236 et seq. ; in 
 Alaska, 45; direction of, 196, 240 et seq.; 
 In Europe, 236; In New England, 237 
 et seq.; In New Jersey, 241; In Pennsyl- 
 vania, 241; in Ohio, 242; In Indiana and 
 Illinois, 243 ; beyond the Missouri River, 
 243 et seq.; In British America, 176, 244 
 et seq. ; on northeastern Mackenzie River, 
 246 ; upward, 246 et seq. ; In Scotland, 484 ; 
 In Africa, 485; In India, 485. 
 
 Transportation of till, 267 et seq.; In Ohio, 
 257; in the Red River region, 258 ; In New 
 England, 269; in Pennsylvania, 259; In 
 Europe, 260. 
 
 Transporting power of rivers,, 638. 
 
 Trenton, N. J., 329; palaeolithic Imple- 
 ments at, 541, 619, 620, 625 et seq., 645, 
 671. 
 
 Trenton gravel, 631-633, 637 et seq., 671. 
 
 Tschernyschev, Professor, 586. 
 
 Tuckernuck Island, 137. 
 
 Tundra In Alaska, 36, 37. 
 
 Tuolumne county, Cal., 13, 180, 689 et seq. 
 
 Tuscarawas River, Ohio, 301, 310, 326. 
 
 Two glacial epochs, 575 et seq,, 607 et seq., 
 669. 
 
 Tyndall, Professor John, measurements 
 of glaciers, 2, 3, 41, 81. 
 
762 
 
 INDEX. 
 
 Tyndall Glacier, 87. 
 Tyrol Mountains, 104, 365. 
 
 Uintah Mountains, 178, 179. 
 
 Unalaska, island of, 36. 
 
 Uniformitarlanlsm, 532, 533. 
 
 Upham, Mr. Warren, 497, 504; discovers 
 terminal moraine, 134; traced moraine 
 through Iowa and eastern Dakota, 211, 
 212; on depth of drift, 258, 259; on drum- 
 Uns, 282, 283, 287, 289, 292; on Brown's 
 Valley, 316; on glacial drainage In the 
 Northwest, 330 et seq.; in British 
 America, 335; on kames in the Con- 
 necticut Valley, 345; on the gravel 
 plains north of Portland, Me., 349; 
 on kame-llke ridges in Minnesota, 353; 
 on lakes of Minnesota, 361, 362; on 
 Lake Agassiz, 401-406, 543, 548; on 
 loess, 415, 416; on Lewis's work in 
 England. 448, 452; on shells near Bos- 
 ton, Mass., 453; on probable causes of 
 glaciatlon, 497; on vegetable deposits in 
 northern Minnesota, 607; on palseolithlc 
 implements, 654 et seq. 
 
 Ural Mountains, lOS, 447. 
 
 Utah, former glaciers in, 176, 177. 
 
 Vancouver on glaciers of Alaska, 22 et seg., 
 30; visit to Disenchantment Bay, 31; on 
 Glacier Bay, 59 et aeq. 
 
 Vancouver Island, 183, 185 et seq., 102, 505. 
 
 Vegetable remains in glacial deposits, near 
 Muir Glacier, 61 et seq., 233, 592; at Point 
 Wilson, 182, 183 ; at Morgantown, W. Va., 
 377, 378, 384, 603; In Teazes Valley, 381, 
 604; theory of, 576, 579; in Montgomery 
 county, Ohio, 592, 593 ; In Butler county, 
 Ohio, 592, 598 et aeq. ; in Morgan, Jackson, 
 Jennings, and Jefferson counties, Ind., 
 601, 602; in Hamilton, Highland, Ross, 
 and Licking counties, Ohio, 602, 603; in 
 southwestern Indiana, 603; in Penn- 
 sylvania, 604; in Minnesota, 605 
 
 Vegetation in the vicinity of Muir Glacier, 
 41, 69. 
 
 Veins in glacial ice, 7. 
 
 Vermont, 104, 247, 635, 665. 
 
 Vessel Rock, N. H., 236. 
 
 Victoria, glacial grooves near, 183, 184. 
 
 Victoria Glacier, 13. 
 
 Viscosity of ice, 88, 96. 
 
 Volcanic outflows probably correlated with 
 glaciatlon, 501. 
 
 Volcanoes Indicating molten interior of the 
 earth, 499. 
 
 Volk, Mr. Ernest, 630. 
 
 Waagen, Dr. W., 516. 
 
 Wabash River, 170, 300, 314, 323, 326, 353, 
 354. 
 
 Wadsworth, Professor M. E., 498. 
 
 Wahsatoh Mountains, 149-179, 274, 336. 
 
 Wakefield, N. H., 351. 
 
 Wales, 446, 450, 453, 484. 
 
 Wallace, A. R., 436, 508, 514, 516-518. 
 
 Wallenpaupack Creek, Fa., 311. 
 
 Walrus, 436, 438, 641, 675. 
 
 Warner, L. C, 106. 
 
 Warping rafts, 351. 
 
 Warren county, Pa., terminal mosaine in, 
 149, 150; prBglacial drainage in, 307. 
 
 Warren, Pa., 149, 150, 307; kettle-hole in, 
 598. 
 
 Washington county, Pa., 604. 
 
 Washington Land, 86, 92, 94, 97. 
 
 Washington, State of, 135, 178, 180, 181; 
 glaciers in, I9etseq., 177, 191, 222. 
 
 Watch Hill, 140. 
 
 Water, peculiarities of Its freezing-point, 
 1,4,5. 
 
 Waterfalls, scarcity of, In unglaciated re- 
 gions, 362. 
 
 Watertown, N. Y., 481. 
 
 Wells in Ohio, 168, 169, 257, 258, 602; in 
 British Columbia, 185; in Pennsylvania, 
 260, 604; in Indiana, 300, 601, 602; near 
 Morgantown, W. Va., 377; in Minnesota, 
 555, 605, 607. 
 
 WeUs, Mr. David A., 238. 
 
 Wenkchemna Glacier, 13. 
 
 Wensleydale Glacier, 449, 450. 
 
 Weston, W. Va., 378. 
 
 West Virginia, 604; terraces in, 377 et seq., 
 603, 604; vegetable remains in glacial 
 deposits in, 377 et seq., 603, 604; wells in, 
 377; transported bowlders in, 379, 382. 
 
 Whirlpool In Niagara River, 536 et aeq., 
 549 et aeq., 551. 
 
 White Glacier, 72. 
 
 White Mountains, Alaska, 43, 61. 
 
 White Mountains, N. H., 429, 438 et seq., 
 519. 
 
 White, Professor I. C, 605; on the Cin- 
 cinnati ice-dam, 197, 370, 371, 384, 603; 
 reports wells in Wyoming county, Pa., 
 260; reports buried channels in Pike and 
 Monroe counties. Pa., 311; on terraces in 
 West Virginia, 377 et aeq., 382, 384; on the 
 Monongahela ice-dam, 391-393. 
 
 Whlttlesey.'Colonel Charles, 500; on forma- 
 tion of kettle-holes, 144; reports wells in 
 Ohio, 602. 
 
 White River, Dak., 173. 
 
 White River, Ind., 601, 649. 
 
INDEX. 
 
 763 
 
 White River, Ore., 19. 
 
 White Elver, State of Washington, 21-23. 
 
 Whitney, Professor J. D., 498, 513; ascent 
 of Mount Shasta by, 18; cited, 108, 176, 
 178; on glaciers of New Zealand, 112; on 
 formation of Yosemlte Valley, ISO, 271 ; 
 on cause of ice age, 464; palaeolithic dis- 
 coveries of, 627; on antiquity of man In 
 California, 688, 692 et seq.; on deep 
 placers of California, 689, 690. 
 
 Whymper on Greenland glaciers, 82 et seq. ; 
 cited, 108. 
 
 Williams, Professor E. H., 582, 584; on the 
 attenuated border, 151-166. 
 
 Wmiamaon county. 111., 170, 171. 
 
 WiUoughby Island, 44, 61, 189. 
 
 Wilson, Mr. Thomas, 623. 
 
 Winchell, Professor A., 501; on the effect 
 of pressure of a glacier, 417, 418 ; on antiq- 
 uity of man in California, 698. 
 
 Winchell, Professor N. H., 508, 517, 597; 
 on rate of recession of Falls of St. An- 
 thony, 552 et aeq., 665; palseoUthic dis- 
 coveries of, 537, 656, 660. 
 
 Wind River Mountains, 13. 
 
 Wind, transporting power of, 408, 409. 
 
 Wlnooskl River, 347. 
 
 Wlnalow, Dr. C. F., 692. 
 
 Wisconsin, 625; drlftless area of, 134, 413, 
 414, 527 ; depth of Ice In, 201 ; kettle-range 
 in, 134, 144, 210 et seq., 221, 361 ; drift hills 
 In, 286; lakes in, 361; loess in, 413, 414; 
 post-glacial erosion in, 568. 
 
 Wisconsin episode, 222 et seq. 
 
 WoeikofF, on CroU's theory of the cause of 
 the Glacial period, 474; on glaciers of the 
 southern hemisphere, 475, 476; on dis- 
 tribution of heat over the earth, 478, 479 
 et seq. 
 
 Wood Glacier, 74. 
 
 Wood's HoU, 137, 139, 204, 205. 
 
 Woodward, Mr. R. S., 295, 503; on rate of 
 recession of Niagara Falls, 540. 
 
 Wright, C. W., 72. 
 
 Wright, F. E., 72. 
 
 Wright, Professor G. F., 508, 517, 665. 
 
 Wright. Professor W. E. C, 349. 
 
 Wyman, Dr., 693.